When I "upgraded" to Vista on my laptop this precipitated a lot of "Firefox has stopped working" and "Thunderbird has stopped working when I used these portable applications. Since I am heavily invested in portable apps, this was a BIG problem. I use an SD card on my laptop for the portable applications. After a lot of experimentation, I found that if I changed the drive option from "Quick removal" to "performance", the problem went away. I think the delay associated with writing the buffers for quick removal made Vista think the application had stopped.
Right click the drive in Explorer, select properties, then select the hardware tab. Then select the drive in question from the list, select click Properties and then policies. Change from quick removal to performance. You will need to restart to get this going.