1. Show us the code!
2. Tell us what modules do you use to connect to the database and their versions (DBI, DBD::ODBC / DBD::Sybase).
3. Tell us what operating system do you use and what version of MS SQL Server.

And please don't be so quick. Even though the modules are not (and cannot be) 100% perfect it's still more likely there is a problem in your code than in the tried and tested modules.