Are you getting an error, or just wondering?
What database and connectivity are you using?
I'm not aware of a limit in Crystal, however you may be experiencing problems with your connectivity. The only time I've heard of this error was on an MS Access database, and once we did a compact and repair on the databse it went away.
I think that Access used to have a 255 field limit in it, so that might be an issue as well.
-k