This behavior is usually caused by the temp folder being locked.
The simplest way to correct this is:
1. Rename the temp folder found in the C:\WINDOWS\TEMP directory.
2. Create a new temp folder in the C:\WINDOWS directory.
3. Run the QuickTime 3 Installer.
4. Verify it is installed by playing the sample movie that is included.
5. Delete the the temp folder you created.
6. Rename the original temp folder back to temp folder.