Error using the READ function for importing a video file

Hi,

I am having trouble with the READ function. Can anyone help me understand what is going wrong based on the output below?

>> videoObj

Summary of Multimedia Reader Object for 'vid1.wmv'.

    Video Parameters:  29.97 frames per second, RGB24 720x480.
                       902 total video frames available.

>> frames = read(videoObj, [35 50]);
Error using VideoReader/read (line 86)
The frame range requested is beyond the end of the file.

Incidentally, the following line works just fine:

>> frames = read(videoObj, [1 50]);

I'm stumped...

Thanks, -Jeff