Been having problems with flow sim giving me this error, when i try to insert a volume heat generation source on a part. Not sure all the different reasons this can happen, but i think one of them may be from using a 2013 part in 2014 version. I opened the part, and just hit save, it automatically converted it to 2014, then I was able to insert a volume source on it.

thought i would share this.

-Shane