One guess, video card setting? The mod;
Webster's Improved US Torpedo for v1.4 and v1.5\Webster's Improved US Torpedo v1
Is the one I'm using, I recently reinstalled the stock SH4 patched to 1.4 and tested before installing any mods, I get the occasional flickers along with phantoms in rainy weather;
What I got;
Operating System: Windows XP Media Edition (5.1, Build 2600) Service Pack 3
Model: Dell DXP051
Power supply: 550 watts
CPU: Intel(R) Pentium(R) D CPU 3.40GHz (2 CPUs)
Memory: 2GB Crucial Ballistix 800mhz (throttled down to 633 because Dell sucks)
Video: NVIDIA GeForce GT430 1GB
Sound: SB Audigy
Hard Drives:
C:Western Digital WD5000AAKX-001CA0 462.0 GB 7200rpm
F:SanDisk SDSSDH120GG25 114.5 GB solid state drive
The flickering and phantom lookout are not annoying enough to bother with, altho I did try stuff like forcing Vsynch on, no change. But I don't get a crash with Webster's torpedo mod. Do you have a copy of the stock game you can test to see if the crash happens without Webster's mod?