I'm not sure but there's a patch for this exact problem.
The problem with the furnace is a known one.Patch.
Or try this one posted by Rushes:
Please follow these steps to fix the issue:
1. Please reinstall the game, no uninstall is necessary, and the saved games will not be lost.
2. After reinstalling the game, apply the new, updated patch from this location:http://download.agongame.com/AGON_Toledo_Patch/AGON_Toledo_patch_int_Setup_1.04.exe