mySQL server has gone away - error upon registering

[robg2251]

A user complained to me that every time they try to register, they receive the error "mySQL server has gone away"..   I tried registering and could get in just fine.    Any idea on this random error?   I searched back and found some previous people had the problem, but there was no direct fix for it.. 

Thanks

[karlbenson]

http://docs.simplemachines.org/index.php?topic=1501.msg4941#msg4941