I don't own scrapebox, So I cannot be 100% sure. But, using the mshtml DLL, what is likely happening is that SweetFunny is using a browser on the backend (Which you guys have more or less confirmed).
When I was selling my own commenter, there is a big big issue with Javascript popup windows. Like those ones when you try and leave a page and they say "Please don't leave blah blah blah".
AFAIK, these were near impossible to get around. And they freeze the browser (You can't navigate to a new page etc). It may be a completely different issue, but I know for a fact that was a problem. And you can't just disable JS either, because that is the whole point of using the slow commenter.
Unfortunately, I develop in a completely different language, so the two error messages cannot be compared. But I would be semi-sure, that this is a problem with Scrapebox (And likely will be near impossible to fix).