I was unable to figure out how to set the Pre-requisites for the class, sadly. I did, however, list the pre-reqs in the description. So there's that.

Thanks.

Hey, Sendric. The Shugenja element focus abilities (Air, Earth, Fire, Water from Complete Divine and Rokugan Campaign setting, a copy in each) need an extra line of script after assigning the elemental spells they use.

They can learn spells with the "All" elemental tag as their elemental spells, otherwise they run out of spells they can learn at 9th level.

Could probably just add it to the base class, but I'll look into it more when I get to that part of the process. Thanks.

The second set of Shugenja custom abilities is actually in Oriental Adventures, but why are they there? Other than a slight difference in the description there doesn't seem to be a difference.

That was me being overzealous when backporting. Sorry :)

No problem. When I finish up with the spells overhaul, I'll take a closer look at the Shugenja and see what changes need to be made to support it as an OA class.

The vampire template isn't disabling Con.

These undead templates have been an ongoing battle. I'll look into it. Thanks for the report.

Validation Error with no explanation
 

I'm getting a weird validation error on a character, it says "Paladin: too many assigned." That's it, that's all it says, and I've tried to remove, then add back all sorts of things to see what is triggering the error to no avail. Any suggestion or help would be awesome - hard to say for sure whether it's a bug with the data set, but I can't think of anything else it could be. Thanks

Delete the Paladin, then you should be fine! :)
Seriously - can you offer more information? Eg: What tab is this appearing on?
You could also post a copy of the .por file with the Hero that other people can look at.

This message indicates its a problem with the class itself rather than the hero. Could be you have too many spells or custom abilities or something like that. Unfortunately, as Dami points out, there's no way for us to debug further without knowing more details. Attaching the .por file is probably the easiest way to do that.