Driver SQL do aplicativo de guerra do Tomcat 7 ausente

Quando implanto meu aplicativo WAR no Tomcat 7 em meu Synology NAS, tudo corre bem na primeira vez. Mas quando quero atualizar o arquivo war para uma versão mais recente, tenho que parar a sessão atual para carregar o novo arquivo war. Quando tento iniciar o novo aplicativo, recebo a seguinte mensagem de erro no gerenciador:

FAIL - Application at context path /Franke2-0.1 could not be started
FAIL - Encountered exception org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/Franke2-0.1]]

Quando reinstalo o Tomcat 7 e uso exatamente o mesmo arquivo war de antes, ele funciona novamente. Mas não quero reinstalar o Tomcat toda vez que quiser carregar uma versão mais recente do meu aplicativo.

Meu aplicativo é um aplicativo Grails e estou usando um banco de dados externo, não integrado ao Grails. No arquivo de log catalina.out, estou recebendo o seguinte erro:

java.sql.SQLException: No suitable driver found for jdbc:sqlite:./database/dataUser.db
at java.sql.DriverManager.getConnection(DriverManager.java:689)
at java.sql.DriverManager.getConnection(DriverManager.java:270)
at home.DatabaseUser.check(DatabaseUser.java:242)
at home.DatabaseUser$check.call(Unknown Source)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:47)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:136)
at franke2.LoginController.login(LoginController.groovy:12)
at org.grails.core.DefaultGrailsControllerClass$MethodHandleInvoker.invoke(DefaultGrailsControllerClass.java:223)
at org.grails.core.DefaultGrailsControllerClass.invoke(DefaultGrailsControllerClass.java:188)
at org.grails.web.mapping.mvc.UrlMappingsInfoHandlerAdapter.handle(UrlMappingsInfoHandlerAdapter.groovy:90)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.springframework.boot.web.filter.ApplicationContextHeaderFilter.doFilterInternal(ApplicationContextHeaderFilter.java:55)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.springframework.boot.actuate.trace.WebRequestTraceFilter.doFilterInternal(WebRequestTraceFilter.java:111)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.grails.web.servlet.mvc.GrailsWebRequestFilter.doFilterInternal(GrailsWebRequestFilter.java:77)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.grails.web.filters.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:67)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.springframework.web.filter.CorsFilter.doFilterInternal(CorsFilter.java:96)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.springframework.boot.actuate.autoconfigure.MetricsFilter.doFilterInternal(MetricsFilter.java:103)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.springframework.boot.web.support.ErrorPageFilter.doFilter(ErrorPageFilter.java:130)
at org.springframework.boot.web.support.ErrorPageFilter.access$000(ErrorPageFilter.java:66)
at org.springframework.boot.web.support.ErrorPageFilter$1.doFilterInternal(ErrorPageFilter.java:105)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.boot.web.support.ErrorPageFilter.doFilter(ErrorPageFilter.java:123)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:494)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:1025)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1137)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)

Já tentei colar o sqlite-jdbc-3.27.2.1.jar tanto na pasta lib do Tomcat quanto na pasta WEB-INF/lib da minha aplicação, mas não mudou nada.

O estranho é que, embora o aplicativo seja iniciado após a reinstalação do Tomcat, o banco de dados não funciona e estou recebendo o mesmo SQLException acima.

Desde já, obrigado!