Also me would like know where the logs are in Jboss, whe it is install with eclipse.
In Eclipse you had to specify a location where JBoss AS was installed, and you had to choose from a configuration (all, default, etc). The logs are in server/xxx/logs directory (where xxx is the configuration) under the JBoss AS location you specified.
Without any details whatsoever about your app, it it difficult to say what the problem is. Of course it doesn't help that the JSF library has a null pointer bug in it and the myfaces developers were not intelligent enough to test for that and give a meaningful error to help pinpoint the problem. You might have to grab the source and add some debugging code. Or turn the trace level up to DEBUG or TRACE for org.apache.myfaces and see if that yields any extra info in the logs.