Deploying problems with Tomcat on Ubuntu

[NemoMaximus]

I have a major problem with deploying my application on my Tomcat 6.0.18 running Ubuntu Server 8.04... Or actually, I can deploy the application and it starts just fine the first time. But as soon as I restart Tomcat or restart the Ubuntu server the application fails to start... In catalina.out I can find the following error message:

SEVERE: Error starting static Resources
java.lang.IllegalArgumentException: Document base /webapps/ubanc does not exist or is not a readable directory
at org.apache.naming.resources.FileDirContext.setDocBase(FileDirContext.java:141)
at org.apache.catalina.core.StandardContext.resourcesStart(StandardContext.java:3957)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4126)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:525)
at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:627)
at org.apache.catalina.startup.HostConfig.deployDescriptors(HostConfig.java:553)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:488)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1149)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:311)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:719)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
at org.apache.catalina.core.StandardService.start(StandardService.java:516)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
at org.apache.catalina.startup.Catalina.start(Catalina.java:578)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)
Oct 27, 2008 2:52:04 PM org.apache.catalina.core.StandardContext start
SEVERE: Error in resourceStart()
Oct 27, 2008 2:52:04 PM org.apache.catalina.core.StandardContext start
SEVERE: Error getConfigured
Oct 27, 2008 2:52:04 PM org.apache.catalina.core.StandardContext start
SEVERE: Context [/ubanc] startup failed due to previous errors
Oct 27, 2008 2:52:04 PM org.apache.catalina.core.StandardContext stop
INFO: Container org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/ubanc] has not been started

What is going on here? Why does it start the first time? Please help!