Windows Movie Maker save fail

My daughter's been working on adding subtitles to a long movie, and finally finished.
Now she is trying to save the movie, and WMM keeps failing.
The error message help suggests that there is no space on the device, or some of the source files are missing - neither of which is the case.
Googling suggested (1) the possibility of file format problems, but her only input files are WMV's (and the subtitles which were created by WMM itself) or (2) lack of RAM, but I've watched the performance monitor while it was trying to save, and the PF was never even 20% used.

Any ideas?

Or, failing that, any suggestions for a free tool that is able to read WMM project files, including the subtitles and timeline and all that (And, obviously, save the resulting movie).

Any help would be appreciated.

Probably redundant, but are you trying to save the WMM project or exporting the movie file itself?

Trying to export the movie file.

Mmm. WMM isn't the best tool out there, really glitchy and small things can upset it and crash the whole thing. From what I read, WMM doesn't like WMV files, so you could try to convert those into AVI or something similiar and see if that helps. It is a whole lot of stuff to do though, but all I can think of from quick googling, so if someone else has other ideas, you should try those first :l You should also triple check that all the files that you are trying to use are there and they haven't been moved around into different folders or anything like that.

not sure if this is your case or not: http://support.microsoft.com/kb/814836

You may narrow down the problem by trying the followings:

• open a new project, import a small video, add few subtitles, export;
  
• open a new project, import only the video(the large one u use), then try export it as wmv;
  
• same as above, with 1 line of subtitle
  
• copy the whole project with sources, try it on other computer
  
• etc...
  

Also, alt. way to add subtitle should be using subtitle software like directvobsub; srt is a common extension...