Hmm... I am entirely unfamiliar with FPDF. Is it possible that the upgrade includes a new version of FPDF and that the usage has changed? Perhaps a feature/function has been deprecated?
If you can give more information, someone here may know. Right now, all we know is that they're not being generated. We don't know how you're trying to generate them, what you've tried to fix it, what errors you're getting, etc...
If you're new to this forum thing, I'd highly recommend reading the 2nd link in my signature. It'll help you write questions we can more easily troubleshoot.
