Campaign Series East Front PBEM

[The Hemp]

A friend and I want to Play East Front by email. I sent him the .bte file for Red Steel at Federovka.  In the set up I selected Axis as my local player and fog of war.  No other changes.  Made my move and sent to him.  He loaded and sent me a text that it shows "error reading scenario file" (quote from his text).  Any advice or thoughts would be helpful.  Thanks in advance.