Issue: problems with posting

I can't post my post O.o
the error say's the message is too short but it isn't!!!
I mean I'm here long enough to know when a post is too short
I tried to post it again and again and loaded the page again and again but I'll always have the same error

I had it some other times too but when I loaded the page again it worked fine like usual
but not now !!! and I dunno what to do