PBEM problems

So Me and a friend are trying to set up a PBEM game. The problem is that when he tries to load the game I sent him he gets a "Load failed" he tells me there is no other information. I own a copy of civ 4 gold whereas he bought civ 4 and then bought the expansion, would this cause issues? We checked in the advanced menu and it tells us we have the same version. Does anyone have experience with this sort of issue or any idea of how to fix it?

ok apparently it also says "the save file you have selected is protected to ensure that the assets in your mod folder have not been changed". Again we both are running the same version of civ :S

Are you running a mod ?

Number of the players in our game (see my sig) have exactly the same issue. And yes, we are playing mod. The strange thing is that some of the players get this error message and some do not!

Maybe worth checking the author of the mod.

Also, you may also want to ensure that all players have installed as per my thread. http://forums.civfanatics.com/showthread.php?t=408537

If you play custom scenarios or mods on Windows Vista or Seven, you really need to install Civ 4 as per my thread. This avoids most of the issues.