Rainer,

I ran the study from that thread a few years ago, so I don't remember all of the details. I was just now surfing the forums regarding a totally different question.

Regarding your situation, I was unable to get MediaLab to run PEBL itself. I think I got as far as you did, where MediaLab would bring up PEBL's launch window. I (or another experimenter) would then have to manually select the appropriate PEBL script and enter a subject number and click "Run" or "Run Script" or whatever PEBL has you click to begin it's task.
I didn't mess with additional parameters and couldn't get PEBL to grab participant numbers from anywhere or have MediaLab send stuff to it. I boil this down to my lack of understanding the language and willingness to take the time to get it to work that way.

A few things that I remember running into that may help:
- Try to have all files consolidated on the local machine. One of the problems I was running into was working from a shared drive.
- For whatever reason, the PEBL launcher had a tendency to crash when it was initially started, other times crashing when I began running the script. Running a study once and running into this issue and ending the experiment in MediaLab and then starting over again sometimes solved this problem.
- Newer versions of MediaLab may be easier to work with as well.

That's all the feedback I can think to give you. Sorry it's come so long after you first posed the question. I hope it helps anyways.