"column name or number of supplied values does not match table definition"

I'm writing a payroll system using VB.net with .Net remoting. When running a calculation routine I enountered this problem and giving me the error "column name or number of supplied values does not match table definition", this problem only occurs when processing more than 400 employees data. the 400 employees data are exactly the same. I've tried reduce it to 200, and it could process without problem the first few times, but when i kept repeating the process, then it will give me the error again. I suspect there's memory leak or something. but i don't know whether it's caused by the stored procedure or the .net remoting objects.
can anyone give some idea?