I am not sure what the problem is. Was this beta version downloaded from my test site or was it checked out of cvs? What version of jboss are you using?
Both of the version from your test site and the one from cvs threw this exception. Jboss version is 3.2.3 and nukes version is post-1.0 (a version I got from cvs after 1.0 is posted). However, I as updated from cvs to the current nukes version, the downloads module deployed just fine.
Yes, the downloads module was deloped using cvs HEAD. It has been tested with this code. If you use anything earlier it is not gauranteed to work.