Thanks to Ivan, I've identified the problem as being related to my virus scanner, AVG. With some fiddling I've even identified the specific component of my scanner, the "Behavior Shield". I've added both BGI.exe file as well as it's containing folder to the the exceptions list. I even added the folder containing the folder to the exception list. So far only out right deactivation of the "Behavior Shield" is helping.
Anybody got any ideas on the next step to try?