Its a bigger problem when ppl are using nulled software such as VBulletin which is the worst, resource killing software ever created. There could be only 1 or 2 visitors online and you will reach 2 simultaneous connections at the same time and start getting errors.
So never use VBulletin , IP.board or datafile.
Use myBB
http://www.mybboard.net/ and you will never get any problems.