I just finished a PBEM game and I want to write it up. I have all (or nearly all) of the saves but I cannot open earlier ones because of the v1.74 patch. Earlier saves were created with v1.61 patch. Is there a way to roll back v1.74 to v1.61 or are we talking about a uninstall / reinstall approach?

unfortunately there is only the way to uninstall and reinstall - there is no simple uninstall routine for the patches :sad:

Instead of uninstalling, I'd probably just rename the "Program Files/Civ4" directory and then do a normal install/patch. That way you end up with both versions when you are done ...