You have to install Quicktime from Apple on your computer in order to use it within Vegas. You must also do a full Quicktime intall including authoring components. The default installation doesn't include authoring components.
I'm having the same issue and took your advice in reinstalling QuickTime. I did not get the option of choosing an installation mode, but instead got a prompt that my ISScript.msi file was outdated.
A visit to the InstalliShield site was less that hepful, as least for me. Is there some easy method of updating this particular file so I can import MOV files into Vegas. I just can't seem to penetrate the ins and outs of Windows XP.
I had a problem with some quicktime files in vms6 platinum. I used the messy technique to use the clips.
1. renamed the clip to a .mpg file
2. played the clip in windows media player
3.used windows movie maker to create a wmv file
4. Now the clip should work in VMS
I found a clumsy work -around by upgrading to VMS 7 and purchasing QuickTimePro. The clip I needed to work with was a 83.7KB .mov file that VMS 6 wouldn't recognize. VMS 7 imported the video but not the audio. So I used QuickTimePro to save the .mov file as an AVI file, which hurt the video but didn't seem to do much to the audio. I then married the audio track from the AVI with the superior video track from the original .mov file and rendered the portion I needed to a AVI. Worked fine, but what a hassle.