Same thing happens to me. I saw a [BUG] fix posted by Tim Rowledge a
couple of weeks ago that I believe addresses this problem, but I haven't
tried it out yet. 

Ross Boylan wrote:
> 
> I just upgraded my squeak VM for Linux to 3.2 gamma.  I now find that when
> I switch to windows, which is running the 5/17/01 (3.1?) VM from Andreas,
> that I can't open the image I saved.
> 
> The symptom when I try to open the image is that I get a dialog box that
> says "SQUEAK: please select an image file ...".  I can open other images,
> but not the one saved from Linux.
> 
> Can anyone offer any clues about what's happening?  I will double-check I
> can still open the image while running Linux when I get a chance to
> reboot.  Also, I thought there was a more recent Windows VM....