I cannot open the file in my old 10; I get an error message saying that Acrobat is having difficulties and the file may be damaged.
I hope others can open it.
your clipping path according to AI document info consists of 82 open paths. Ungroup several times and use JET's join nearest script on the 83 paths, works like a charm with 1 path consisting of 181 points
I'm looking in CS4, which can do odd things to clipping masks, but as said above, your clipping mask seems to be itself clipped by all of the bits that you snipped out of the border shape.
Tip down the arrows in your layers panel to dig down to the issue. Click on the dot on the right side to select via the layers panel.
 If you delete the group that is all the extra bits, the remaining shape is your desired (I assume) clipping mask.
Oh, is that what's wrong then? My paths aren't closed? Where is the script please?
Thanks. I tried deleting the groups but that just then deletes the mask. I think it may be to do with the fact they aren't joined.
You don't need to delete both groups - one appears to be (what I assume to be) your desired mask. Just delete the one that I show selected in the above screenshot.
It looks like you use pathfinder->cut to get your "sawtoothed" shape but then used the shape as well as the cutouts from the "teeth" as clipping masks.
However you do it, you just need to isolate the one object - I recommend using the layers panel.