This had some good moments, but overall I've got to agree with johnhummel. The guy is condemned to hell for having a sex chat, and nothing he can do after that initial bout will possibly get him off the hook. Why is he still paying child support after his son is a grown man, anyway?
Any fair court would be able to obviously see that he wasn't aware of the possible of pregnancy over an internet line. As a normal mortal, he was presumably unaware of the real existence of succubi, and in any case, traditional succubus stories do not cause pregnancy over the internet so how would he have known. Of course, the Devil's court is no fair court, but then what's the point of having a trial at all if there's not even a semblance of fairness. After that ridiculous decision, why wouldn't you appeal to a higher court (as in Heaven). Can't he repent his sins and be forgiven? Perhaps not for his debts in his lifetime, but to prevent eternal damnation at least?
If this were made into a movie, it would star Ben Stiller. It reminds me much of most of his films where there's a regular guy subjected to escalating, ridiculous, unrealistic trials from people who all seem at first to be normal, and everything bad focuses only on him.
And I also agree with Russell that the title gave away the ending, so the element of the surprise was blown long before the end was reached.