Did it work before ?
If yes your regexes do no longer fit the (german) warning messages or are lost.
See here for a simple workaround: http://forums.codeblocks.org/index.php/topic,9489.msg67127.html#msg67127
Instead of "en_US.UTF-8" a simpls "C" might also work.
Regex that should work for german and english compiler warning:
([][{}() \t#%$~A-Za-z0-9_:+/\.-]+):([0-9]+):[ \t]([Ww]arn[iu]ng:[ \t].*)