These are only the results of me checking each non-dev-team-submitted room individually, so I might be missing something. Also, I only bothered to check the wizardland room descriptions. However, I think the problem is only with dungeon/tesla_coil.png being located in the rooms "Simple Forcefield Maze" and "Frankenshteen". tesla_coil.png is an expansion2-only file. Everything else referenced blockers located in the base /dungeon/ directory or expansion3's /dungeon/ directory.