No idea, though I'm sure I can't do anything about it. Thar be the dark waters of database.
If you have SA access to the db, it should be a relatively minor change to update the field properties on the table to allow more characters.
Of course, you could also hose the entire board if you made a mistake so think long and hard before playing with it if you do.
There's also the possibility it may be a problem of the coding on the page no accepting input of certain character length if the db already allows it. That could be updated with much less risk.