Vienna Instruments with SONAR X1

Hi all,
 
I'm using a registered copy of SONAR X1 along with Vienna Instruments ().  The tools are working fine but when I close down SONAR X1, I find that SONARPDR.exe is not removed from the list of processes running on my PC.  This appears to stop SONAR X1 from ever starting up again unless I kill the SONARPDR.exe process tree.  This only happens when I install the Vienna Instruments plugins to SONAR X1.
 
Please can anyone help?
 
Thanks!
 
Chris