If the program you sent to it is using the COMM Port for its own communication then it will interfere with the ability of the TLServer to transfer program to it.
Turn on DIP switch #4, the POWER OFF and ON to reset the PLC. Now it will not run any program and its COMM1 is set to 9600,8,1,n.
Now go to TLServer, open up the serial port setup and set the comm port to 9600 bps, 8,1,n. Try to communicate with the PLC by sending it an "IR*". If successful it will respond with "IR01*". Then send it a blank program. You can turn off DIP switch #4, reset the PLC and change baud rate in TLServer back to 38,400.