BB Code replacement may not be properly formed

[kh99]

I don't see anything wrong with it. The message says "may not be", so I'd say try just hitting "continue" and if the bbcode works, don't worry about it.

ETA: It looks like the code just checks in the replacement string for something like ={param} or ='{param}', apparently in an attempt to warn you if you try to use it as an html attribute without double quotes. So I think you can ignore that message.