I have a bit of trouble...

I am running 1.29b2 on Mac, with GOTM 23, 24, and 25 installed. I'm running Panther, if that's any help.

The install process has changed your default resources.pcx file, and you need to change it back. :) Have a look at this post (http://forums.civfanatics.com/showpost.php?p=1990714&postcount=4).

The installers get you as far as GOTM25. But the last few gotms do need a bit of file swapping to get the correct resources.pcx (plus shadows) and pediaIcons.tx files in place. This is not Mac-specific - the PC installers are the same.