Visual Prime working in v.2008 but not v.2006

I used a trial version of DirectRT v.2008 to create a visual priming manipulation. It worked very well, but when I tried to get it to work on our lab computers (which use the older DirectRT v.2006), the stimuli that was supposed to be subliminal were visible. I tried changing the timing, but even this did not work. After reading several other threads, I tried adjusting the resolution and refresh rate on the computer to 800x600 and 75hz. Also, I checked the log files and found that the stimuli were supposedly being presented at 14-16ms which seems suspect to me given that I, and others, could see the stimuli. Again, this all works fine in v.2008, so I am at a loss to understand what is going wrong. Do you have any suggestions for getting the priming to work on v.2006?

First thing I would do is confirm that it's a version issue. Can you install the same version of DirectRT you have on your non-lab machine onto one of your lab machines and see if it operates the same way? That would help us to tell if it's a difference in hardware or software. If you tell me the exact version of v2008 that you have, I can confirm the location of the download and I'll be happy to give you an authorization code to test it out.