JBoss Tattletale generates its reports based on Java archives and not source code. Make sure that sourcedir you specify when running JBoss Tattletale contains the Java archives (f.ex. .JAR files) that you need scanned.
JBoss Tattletale needs to process the information it gathers in memory, so you need to provide enough memory for that to happen. You can ajust the -Xmx parameter of the command line below if you are using Sun's Java Runtime Environment.
java -Xmx1024m -jar jboss-tattletale.jar <sourcedir> [<outputdir>]
We can't cover every single issue in this guide, so feel free to drop by our forums to see if a solution has already been provided. Otherwise feel free to ask your question there.
Our forum is located at http://www.jboss.org/index.html?module=bb&op=viewforum&f=320