Windows Movie Maker - Timeline Problems, and AutoMovie Problems

Hello.

I'm having some major problemns with my Windows Movie Maker application. It
first started a while ago, but I haven't had time to do anything about it.
Heres my problem:

I open up WMM, and import a few video clips in AVI format. They appear in
the collections pane, and also play in the peview screen when you click on
them, and press the play button. The problem comes when you try and add them
to the timeline. I drag them into the timeline area, and let go to drop them.
Nothing happens. No changes to the timeline, and no error messages.

I thought this might be a problem with the type of file, so I tried it with
some music, and photos instead. Still the same problem.

I then thought that prehaps the problem might be with the timeline, so I
clicked the AutoMovie button to see if WMM would create a movie for me. I
followed the on screen instructions, clicked OK, and an error message
appeared saying: Invalid Pointer.

Finally, I thought that downloading a different version of Windows Movie
Maker from the Microsoft website might solve the problem, so I downloaded
version 2.6, and gave it a try.

No luck. When it first opened, it sent me some error about corrupted
collections, and hen I clicked OK for it to create a new collections file. I
then tried to import the same video clips as before, and got this back:

---

C:\Users\Christopher\Documents\Trains\October 25th\SDC10993.AVI could not be
imported. Unspecified error

C:\Users\Christopher\Documents\Trains\October 25th\SDC10994.AVI could not be
imported. Unspecified error

C:\Users\Christopher\Documents\Trains\October 25th\SDC10995.AVI could not be
imported. Unspecified error

C:\Users\Christopher\Documents\Trains\October 25th\SDC10996.AVI could not be
imported. Unspecified error

---

I haven't got a clue what this means, or what caused it. At the moment, I
can't use WMM at all, because obviously without a working timeline you can't
produce movies!

Thanks in advance for any suggestions you might have for me.