Had a hell of a time chasing an inexplicable and sudden crash in one of my JScript programs last week. In the end Internet Explorer 8 was the culprit.
Thankfully removing IE8 is simply done via the Control Panel and it's rolled back to the previously installed one. Guess we have fair-competition rulings to thank for that or else IE8 would have been impossible to remove without damaging Windows.
Anyways, if you have IE8 installed and you run JScript in WSH, watch out, your program could crash under certain conditions. As for VBScript or other languages, I haven't tested them, so can't speak to those.