Error 53: File not found

I am running Medialab 2008 and the DirectRT beta on a Vista machine. I have previously run earlier Medialab/DirectRT combos many times on XP machines, and I am using those older files. The problem I have is that Medialab does not appear to recognize .csv files that are placed directly in the experiment file. I keep getting the "file not found" error. I have tried re-inputting the .csv files to the experiment file and this doesn't help. There shouldn't be a path problem because I am using relative paths (no c:\...). The .csv files run fine through DirectRT directly. Any idea what I can do? I'd rather not have to go back and recode everything.

Additionally -- when I create a new questionnaire file with the DirectRT .csv file in it, Medialab freezes on a blank screen trying to run this. I should mention I am using a licensed copy of Medialab and a trial copy of DirectRT (wanted to make sure it worked first).