This is the same blacked-out EPA problem reported above, but for me it happens only with any of Nirran's
Mods I wrote for Megamod installed, including either of the two explicitly referenced in the MegaMod .ini files ("Mega Custom Books" and "Mr Fixit Stims)
Here is the procedure I use:
1) Humongous installation from US 1.2 CD
2) Delete PATCH0000
3) Copy megamod 2.44 contents, install/overwrite in Fallout2 installation folder
4) Run ProcessDat2
5) Copy/overwrite with Drobovik's script fixes
6) Confirm all files in Data\proto\critters and Data\proto\items are read-only (they always are, but I still check)
7) Play to EPA, save game before EPA, copy save folder, confirm EPA looks good on entry
8) Copy a Nirran MegaMod mod, overwrite conflicting previous files (tried leaving all original MM2.44 files in place instead, and of course, the mod did not take effect), and make adjustments to .ini files if applicable (ie, stimpack and book mods).
9) Set all files in Data\proto\critters and Data\proto\items to read-only
10) Load game, enter EPA, and run around in the black hole.
11) Uninstall, clear registry, and start again at step 1, but with the save file to clear the hassle of playing-through to the problem area
I have only confirmed this problem with the Books, Mr Fixit Stimpacks, and Weapons upgrade mods.
I am using Windows 7.