7, and to a lesser extent, Vista, protected the Program Files (and "Program Files (x86)" for 64-bit versions of Windows) folders from users. It creates a problem when programs that run under normal User privileges require change or write access to the contents of Program Files.
This was done to "enforce" what MS has been telling developers for more than decade - to separate application programs from the data they write. Unfortunately, some applications - including many games - don't follow the guidelines for reasons I cannot understand. This game, for example, has you put user mods into the program files tree, so off the top I think the issue you are experiencing is that without admin rights the game is trying to write some data to one its folders - which it cannot do without admin level rights.
There are several ways around this, but there are caveats to each approach:
* Install problematic games to a folder outside of Program Files or Program Files (x86). For example, c:\Games\CivilizationBlahBlah. This risks breaking any mods or perhaps the game itself if they hard-code default paths to look for the game under ..\Program Files\
* Run the game as Admin. One way to do this is to launch the game via right-click context menu and select "Run as Administrator". You will get a security UAC prompt when doing so, and it is inconvenient in that regard, but it should work, and doesn't reqiure reinstalling to a custom non-default folder.
There are several variations to that last idea - including taking folder and file ownership under the user account for Program Files or for specific folders under program files, but I can't recommend that - it creates a security risk that cannot be resolved. I mention it for completeness.
