Hi
If you load an .avi file to the media list which is longer than the cut off length you seem to be getting, and without putting it onto the sequence line you switch to LIST VIEW for the media window, what duration is listed for the clip?
Under normal circumstances there is no upper length limit for video clips save cache memory and your patience while loading. There is no setting to alter this.
Image clips are not limited to duration either as you suggest but unlike videos, there is a setting that can be used for this purpose.
As Borate asks, what version of VP are you using please?
In a lot of cases problems get resolved if you re-install the software. Have you tried this?
Nat