When you execute a SSIS and a script task failed, you have only the message indicating the script task failed.
To retrieve the error message, here is the solution. Use a try catch bloc and write the error in the log.
Try 'Write your code here 'Return the succes result Dts.TaskResult = Dts.Results.Success Catch ex As Exception ' post the error message we got back. This is the old error catch code that might work better with SSIS. Dts.Events.FireError(0, "Script Task Error", ex.Message.ToString(), String.Empty, 0) 'Return the Failure result Dts.TaskResult = Dts.Results.Failure End Try