I had that same runtime error. Uninstalled the game and then reinstalled it and now it won't even start up. Looking at the ogre log it states this in the few lines before the game shuts itself down:
20:54:32: Plugin successfully installed
20:54:32: *-*-* OGRE Initialising
20:54:32: *-*-* Version 1.6.4 (Shoggoth)
20:54:32: Path for saving is ... C:/Documents and Settings/Kenneth Sprouse.RENEGADE/Application Data/Runic Games/Torchlight/SAVE
20:54:32: Setting YRatio Init - 0.78125
It seems that as soon as ogre starts to initialize the game crashes. This same issue has occurred numerous times. I'm running an AMD Athalon 3200 (1.6Ghz) with an Nvidia GeForce 5500 with 256MB of video memory and 2GB of RAM. Game was working okay until I installed the second patch then I began to have problems. Thought it might have been the place I bought it from so I got a refund and bought the game directly from runic (newest release) and now the game won't play. Unstalled the vc 2008, rebooted, tried safe mode, reinstalled vc2008 and vc2008 sp1, rebooted and still game crashes. I hope they get this fixed soon. This is a very sad release from the same team that created Diablo II.