You can go to Tools>Options>New and Changed in LabVIEW 7.x and uncheck the Enable automatic error handling dialogs. This won't remove the fact that you are actually getting an error and you should have some form of error handling in the program. What is the exact error code that you see? Normally a timeout eror occurs when you don't read any data at all or the number of bytes available does not match what you specify. Do you get anything when you get the error or is the message shorted than you expect? To avoid the latter, you can use VISA Bytes at Serial port to determine exactly how many bytes to read or if the instrument sends a termination character at the end of the data, make sure you have term character enabled when you call VISA Configure Serial Port.