I have not heard about any similar issue before and I am fairly certain that there's nothing in the script that could cause this. What's not entirely clear to me is whether you are running the script via Inquisit Lab or via Inquisit Web. It would be great if you could clear that up.
It would also be good to know (a) whether you've made any significant changes to the script (if so, which?), (b) if there's anything special about the way you launch the script (e.g. using <batch> elements, via the command line, etc.), and (c) whether you are using an up-to-date Inquisit version (if not, please update).
A screen shot of the actual pop-up message might also be helpful. Thanks.