Urgh, horrid error message. Anybody since this before?

maybe an you missed a closing tag

Yeah, could be anything. Likely a data issue of some kind. Without seeing all your code would be hard to diagnose. You could back up your template, and start removing chunks of code to try and zero in on which section is causing the issue.

i use to get this a lot. Since, I always keep versions and backups and save frequently.

@Talib Jaffer if you didn't know, NS actually does store old versions of your PDF templates as well. You can see the version # at the bottom of the page and use

&version=X

in the URL to go back to old versions. Still a good idea of course to always back up your own work and keep your own versioning, but also nice to know there is a failsafe in NS.