Sorry for the delay in getting to you.  Was you trying to test the serial port or just running full diagnostics?  This is a loop back test for the serial port, so it could mean the port is not functioning correclty.  Unfortunatly it will mean a system board change if the port is defective.  If you haven't noticed a problem with the serial port I suggest testing a serial device on it shortly and see if it works correctly.   

TB