SH2 CTD problem Help plz
 

Every time my brother plays SH2, at various times in the single player campaign, the game crashes to the desktop and gives him this error:

error -1 [pObj == 0]
Directx code: "unrecognized error: 0xffffffff"
F:\Devel\SH2\Sim\Sources\CSH2Sim.cpp
Line 835

(I'm 99% sure this is the correct syntax, as I transcribed it by hand)

This is an unmodified SH2 install, with patch 1.1
What's going on, and how do I fix it?