It means that:

1) you're trying to insert/update a string that's too long to fit in a colum
2) are performing some sort of numeric operation that produces an overflow

Perhaps more, but these are the most common cases.

Martijn Tonies
InterBase Workbench - the developer tool for InterBase and Firebird
http://www.interbaseworkbench.com

Upscene Productions
http://www.upscene.com

"This is an object-oriented system.
If we change anything, the users object."

Hai

can any body tells me why this error occurs.

ISC ERROR CODE:335544321

ISC ERROR MESSAGE:
arithmetic exception, numeric overflow, or string truncation