Having problems decryting messages sent through FireGpg with WinPT

Possible someone can help me.  My brother is using winpt with firegpg on a windows box sending them to my gmail account.  Ive tried copying and saving the sent letter to a file and then decrypting it manually at the command line however always get an error.  I finally asked him to write the letter in notepad, encrypt in manually with WinPt (not through the firegpg interface) and then send it to me.  This method worked successfully.

So my question is:

Is there some flags or something else that needs to be specirfied on the command line, for firegpg to work successfully with winpt?