Adamantyr

I am unable to complete this dungeon because there appears to be a flaw. In a long section of corridor, an invisible "wall" which is to prevent me from advancing, is further south than intended, which prevents me from reaching the switch stalagtite to deactivate it. I am unable to proceed in this dungeon without this being fixed. I'm running the PC version of Avernum 3 on an Athlon 2gh machine, running Windows XP. If you require any additional information, let me know. Adamantyr