If its an In-point and Out-point problem, as suggested, then the footage will play back at the proper speed, it will just cut out before the end. If the footage is the wrong speed altogether, then you used the incorrect project settings when you created the project in VisionLab.
When you create a new project, if you use the New Project... Select Movie" option, it will automatically select the correct project settings, based on the clip you select. The "New Project... Blank Timeline" option, allows you to manually set the project settings, so it is up to you to make sure that you get them right.
If your framerate is wrong, this will definitely affect the playback speed. If the scan method is wrong, this can also affect the playback speed, even doubling the speed in some cases. In either case, how much difference in speed you end up with will vary depending on the exact settings you select, and the settings that the footage uses. This knowledgebase article
deals with the subject as well.