My error when i write /? in minecraft chat : http://pastebin.com/rFe9Ntu9

Have you tried ? instead of /?

Sorry for taking so long to get back to this. Did you resolve the problem? This looks like an error in one of your conditions in your rules file. Eg:

match blah
ignore string ?
then whatever

This isn't a bug in PwnFilter, per se, though it would be nice if we had a more friendly handling for unescaped regex in matches like this.

If you're still tracking this, please let me know, otherwise, I will close it in a week or so.

I see... The problem is actually in one of our sample files:

match ^/\?
rule A4
require command ?
then deny

I have fixed it by escaping the ? in the "require command" line.