How to play Vassal via email?

Chaps,

I've been trying to play a CCN game via email without much success. I open the file, make my move and then save the game. I email the file to my pal, but he isn't able to open it.

Any suggestions?

Both use the same vassal version,
current the version 3.1.19
and the same CCNapo module and version?

Then it should work.

Starting a logfile, after finishing turn, save logfile (NOT a savefile)
and send it to your friend.