Movie Duration Problem with QT 7 and applescript

I’ve written an applescript that imports an HREF track into a movie. This worked great prior to upgrading to Tiger. Now I get an error when it reaches the part of the script that deals with the movie’s duration:

set mainDuration to the duration

I always get an error that says “Can’t make duration into type reference”.

Did they change the way movie durations are called in QT 7?