I know that this post is kind of old, but maybe this helps somebody:
I got the same error and found a solution for it.
The name of the directory in which I worked contained " - ". I renamed it and removed the spaces and replaced the “-” by “_” and after that it worked. Although the size after and size before doesn’t work anymore but I couldn’t figure out why that is and to be honest: I don’t really care…
That helped, thanks! However, I didn’t have a dash, -, in my folder; I had renamed the original main.c to main-orig.c and it choked on that. You saved me HOURS!
I have a few more information on this. Since my hard drive crashed I had to reinstall my Win7 and had to dig into this again.
The problem seems to be that the utils which come with Winarm 20060606 are out of date (quite obvious) and thus are not working with Win Vista and 7. A workaround is to update the files from somewhere else. On the Winarm homepage there are two test releases (20070505 and 20080331). I took the utils from the latter. Another possibility should be to update the utils directly from MinGW. That’s the place they were taken from in the first place.
Another possibility could be to use Gnuarm instead, but I haven’t tried this.