I don't know if this problem is related to Windows XP or not, or whether it's fixed in one of the updates to DVDMaestro that I don't have. Whenever I drag a video file from the Asset area to the timeline, I get told that the Video Asset is longer than the maximum allowed.

Does anybody know what this means and if there's a workaround, or do I need an update?

The properties of the video look fine - it's a 12 minute video (and the properties say so), so it's hard to believe it's actually longer than the max allowed.
Thanks for any info