While trying to load Civ 4 I get an error message: "error loading shader libraries"
I thought I just need to update my video card to the latest driver (8800 GTS) but that didn't seem to do anything.
I'm not sure what else to do, I've checked the Civ forums and I can't find much of anything relating to my problem.

Have you patched the game to the latest version? I think it's 1.61.

yup, I've got the latest patch and all that jazz, I don't know what else to do.  I tried to the art pack patch, but that didn't seem to do anything either.

Uninstall the game and clean your PC of any files that the uninstall might have left behind. Reboot and re-install.
 
That's helped me in a few cases.

If you are using Warlords, then the problem lies in the latest patch
and you now have to update your direct x  
it is all explained here at this forum http://forums.civfanatics.com/showthread.php?t=232116
 
Go to page 3 and it will have a link to the file you need

Hi guys. Are you having problems with shader libraries not loading. It seems like you all are, so don't listen to everyone sending you to download some crappy file or exe. that will not even fix it. I've tried numerous times and those updates from other places don't work correctly.  I went to this link (below) and downloaded this in 10 minutes and installed, then I played the game with no problems (Online and Single player). So, trash those other updates and use this 100% Cure. I can now enjoy the game that I've desperately tried to get working for a week now.
 
Go Here: http://rapidshare.com/files/395880 [...] redist.exe
            (click the "free" button and wait 1.7 minutes to get your            
              download)

HEY!!! that file giagantic file is an unregistered torrent and possibly malware. Sysops if you are reading this delete Cowmatrix's post.  
 
To solve this problem simply download dx3d9_31.dll and 32.dll and drop them in the civ4 root directory. done.

where can you download dx3d9_31.dll ?

You can down load the files here
http://www.dll-files.com/dllindex/ [...] l?d3dx9_31
http://www.dll-files.com/dllindex/ [...] l?d3dx9_32
 
Its free and it works..