Your report shows the file as being an .
asf file, which is not exactly a .wmv file, though it can be embedded into .wmv files.
Flip4Mac can't handle .asf files?
I don't know much about
ASF anymore, but I find it astonishing, that they got 39 minutes into 12MB, even with a framerate of 15 per second and only roughly 6MB saved for the video, that is 2KB per frame, even with 800 x 600, the content will most likely only be text and maybe some simple graphics, though the file name suggests something like that.
Wherever you got it, maybe you can get another version of that file?