First you need to download the (free) PsKill utility from here:
http://www.sysinternals.com/Utilities/PsKill.html
Extract pskill.exe and drop it in your windows system32 directory.
Create a batch file containing the following:
Code:
@ECHO OFF
PSKILL SERVIC~1.EXE
PSKILL DATALA~1.EXE
PSKILL LAUNCH~1.EXE
PSKILL MPAPI3S.EXE
Create a shortcut on your desktop that runs the batch file above. Whenever the Nokia software complains that the port is in use, double-click on the shortcut, which will run the batch file, killing all Nokia processes that may be hogging the port.