seems to work fine here... no stray BBcode tags when I previewed it.

Try posting it, pre viewing works fine here aswell, but once you post the whole thing, you get an INVALID BBCODE error.

I did a test and for me it works.
I made a fixed version here http://pastebin.com/umU2XDSP

Same goes for you, can you post the whole thing in that case, please?

yep. got that error. weird stuff. Huh