Sorry for commenting on this old thread, but this the first result in google and bing, and I had a workaround that worked for me that I wanted to share with everyone.
Installing PSTCaptureAgent.msi in compatibility mode:
Right click PSTCaptureAgent.msi > Properties > Click Compatibility tab > under "Compatibility Mode", check "Run this program in compatibility mode for:" > click the "Run compatibility troubleshooter" > click "Test
the program" and the installation wizard will start.
Just go through the wizard and install the agent.
I have been able to run a PST Search on the agent and it returned result.
Have not tried to import yet, but this may work fo