After contacting JBoss support I got the sources.
After debugging with the respective sources, it became apparent that there is a problem with the package names which seem to be teh same as some class names (case sensitive). Example -
If one creates a jsp with an import a.b.c.*, that will fail with the above error (the import a.b.c cannot be resolved). Hope they get to a solution, but, regardless, changing the name of the class or package should resolve the issue (as a workaround, otherwise pretty annoying)