3050 Couldn't Lock File

Hello,

I am attempting to run my experiment file as usual in MediaLab v2008 1.33 on a machine with a Windows XP OS. Teh experiment worked twice today without any sort of problem. I then had a Research Assistant log-on to the computer and open MediaLab and the experiment still worked. The computer locked due to inactivity (the Research Assistant left). As such, I restarted the computer, logged in, and then attempted to open the MediaLab experiment file again. I then received the '3050 Couldn't Lock File'. I continue to see the error every time I try to run the experiment in MediaLab. I tried restarting the computer and reopening MediaLab. I am not an administrator on this computer. A few months ago, the lab director created a username and password that everyone in the lab can use so that things are more streamlined. Using this lab account does not remedy the problem (I thought this could resolve any adminstrator issues). Do you know what the problem may be. I have participants to run tomorrow. Please assist. Thanks in advance.

-lhoggard