Dunno if this is any help at all.

In doom 3.
All images are kept in pk4 files. Essentaily pack files.
To make doom 3 run faster You could extract the pk4 files to there current directory. then delete the pk4 files.

This ment that doom 3 nolonger had to extract each file as they were needed.
This helped the game's FPS imensly.

This should apply to RTW as well.
try unpacking the contents.

And mooving the pack file els where.
See if rome will run without the pack file being there. And can just use the individual files. As it did in doom 3.