Generate FA Report Java exception

I’m trying to auto-generate a FA Report from developer by calling the service wm.b2b.editn.FAReport:generateFAReport. I’m getting a Java null pointer exception even if I fill every input variables. I was looking a the source code of the “FAinvoke.dsp” web page (from http://myserver/WmEDIforTN), wich is doing what I’m trying to do and the file is calling the service exactly the same way that I’m doing… Any one of you had that problem before?