BMW's card creating guide should have a list all of the stat tokens available, are you using v1.1 of the guide, link is below for it. The errors stat is listed but it doesn't work. Besides add_background and has_team I don't think anything else was added between the guide and OOTP13.
http://www.cbabaseball.com/public/Cr...011%20v1.1.pdf
The refractor part is looking good.