Thanks. I've been a 'guest' for quite awhile and finally decided to join. Luv Civfanatics!
My OS is Windows XP Pro.
I uninstalled all of Civ 4 (BTS, Warlords, etc) except for a few mods. Then I installed Civ 4 Vanilla to the E: drive (External HD), which it allowed me to change the destination. I tried Warlords (but unlike other posts I read) I never saw it 'change' from the default C: drive to E:, so I cancelled the install. I then installed BTS & it did in fact change the install to the E: drive after doing an update to Civ 4 Vanilla. I then ran the BTS 3.19 patch.
So far when I use the shortcut (which I checked & is pointed to E: drive) or go into HD & try to run it, both Vanilla & BTS start to load properly. The flow of XML errors begins at Load XML (uncached).
Thanks for your help. In the future, a sticky on how to properly install Civ 4 (et al) onto an external HD would be helpful as I searched for 2 hrs and still found no results in the forum.