Just for the record, yesterday I had major problems with posting messages on forum. I managed to post a reply on test forum but everything else wasn't so successfull.
Every submit on post, reply, new topic gave me back "Ooops, something went wrong..." error message.
Yesterday the database had run full (too many posts too quick), which gave problems when posting new posts.
But I now have expanded it to twice the size, so there should not be problems with posts now... I hope!
Nice... I thought it was something wrong with mine browser or sessions, cause I saw other new posts in that period...
Anyhow, now it's working ok.