FS crash when loading AI - part 2, with more insight

Since I last posted my problem I was able to do and test a couple of things, and the result is a riddle I simply cannot solve: I did not found any reproducable errors. Checking all my plans and all my aircraft I managed to crash FS several times - but it was never specific flightplans nor specific planes. Example 1, aircraft: when selecting a certain PAI ERJ-145 repaint in FS, it crashed twice. Thinking I had found the error, I tried a third time - and FS did not crash.Example 2, flightplans: when I tested individual flightplans, they were fine. When I tested stacks of several plans that I had found to be "fine", FS crashed. Also, larger traffic files (approx. 6-7 MB for a traffic.bgl) tended to lead to crashes.What I conclude is that there is some corrupted file or "mechanism" somewhere that simply cannot deal with "too much" traffic, and sometimes has trouble dealing with certain aircraft or textures (and sometimes not).Reducing the traffic % is not an option for three reasons:1) I wouldn't enjoy FS anymore2) I don't see why I should. Just before installing all these new plans (=summer 2006 schedules) I was running a setup with summer 2005 schedules, I had more plans, more flights and more legs, and it worked fine3) It won't solve the problem, because even at 1% FS may be loading some aircraft that it doesn't like and simply crash.Could anyone give me a hint what I can check for- in terms of hardware setup - in terms of any particular files that are needed for AI to function and that may be corruptedBackground info: I run Windows XP-SP2, I have a 2.8GHz Pentium, 1024 MB RAM, a 128 MB graphics card (although 64MB of that are taken from RAM), the swap file is 3 MB IIRC, system sits on drive C:, FS on drive D:, none of which is full, both are virus-checked and de-fragmented.Thanks for any help! I am completely lost.ChrisPS: I'll post the same thread at AVSIM, just to widen the reach of my question which I have a feeling is a tricky one.