I'm having the same problem. Random crashes to desktop (GTAIV.exe has stopped working)
It's happened in a gunfight, while arresting somebody and while just driving around. I'm not using any modded cars so that probably isn't the source of the crashes, and apart from LCPDFR the only mods I'm using are ones I've been using forever (Although that doesn't entirely narrow it down since it could be conflicts, depending on what, if anything, Nick has installed).
The one thing I've tried was after the second crash I deleted Traffic Flow since I read in another thread that that caused problems occasionally.
The other difference is that I'm using base IV on the latest patch rather than TBoGT or TLAD.
I found the problem, don't know if it'll be the same for you, Nick. I reinstalled and installed mods one by one to see which was causing the problem (Doing LCPDFR first, and it worked fine). It was iCEnhancer, probably some incompaibility with 1.0.7.0. I forgot I'd been using a different tweaked ENB for my EFLC install because of this exact problem.