I am having a very similar problem with an experiment that one of our labs is trying to run.

Windows 7 running Medialab 2008 w/ DirectRT 2010. When MediaLab starts up executeDRT.exe ... the system hangs at the white/purple-ish screen for about 50 seconds before executeDRT.exe seems to finally pull up the experiment. We can then run the experiment without any problem. Is there anything that can be done to prevent this delay? I can't figure out what is causing it.