That's
your error message that gives no specifics, actually. When an exception is thrown, it's a good idea to print the stack trace. This tells you what class of exception was thrown, and what line of code threw it. Like this:
But for now I'm going to guess that the exception occurs when you try to execute the SQL insert statement:
Perhaps the employees table doesn't have exactly three columns. Or perhaps not all of them contain
string data. Or perhaps the first one only allows strings of three characters or fewer. At any rate something's wrong with it, and you would have to check your table definition to find out just what. That's assuming that my guess was right about what line of code is throwing the exception.