As that's not BG2, and the line is different, I wouldn't give too much on that "portrait bitmap" thing, but as a general impression, it seems to be caused by corrupt data.InfScreenLoad.cpp at line 1492
Corrupt portrait bitmap. Go into the directory of the save game that is giving this error and delete all the .bmp files. Load the game and then re-save.
Clean the cache of PS:T, try another savegame, or re-install, I'd say.