Open the forum in a new browser window and check the topic you posted to. You will probably find it has gotten through.
Apparently the posts are getting through it just isn't "finishing" properly. If you use the back button and submit again you create a double post.
Posts are getting through to the forum. There seems to be a problem after the submission that is causing the error. I have no idea what this is and I can't do anything about it. The only recourse would be to PM or email... Agent Smith? I think that might be Mike or the Lost Marble user.
I am a big contributor to the forum... but I have no powers beyond the ability to delete double posts or move topics around.
Let's hope whoever IS in charge here is aware of the problem.
-vern