Please place the campaign .cpx file into the Scenario folder instead of the Campaign folder. This change was made to isolate core game files from user created files, so if Windows restricts the ability of the game to save/modify files under the protected Program Files folder in the future, the (disabled by default) per-user save feature will still allow for custom campaigns. Sorry for the trouble!

Got it, thanks!

I had this problem too and didn't know there was such an easy fix.

I always booted back into my old 1.0c .exe to play custom campaigns.

Yea I tried doing that too, but now most custom scenarios use the latest userpatch features, and without them the game either crashes/bugs or is not as fun.