My 4th grade daughter's teacher has the class working on a project using Tux Paint.  We downloaded it today, but, for the life of us, have been unable to get it to save my daughter's project.  When we hit "save," I see what looks like an error message underneath the color palette stating "Couldn't open data/starters/worldmap_japan-back.png."

Just to walk through the problem, when we hit "Save" (the sixth icon down on the right underneath the "Tools" double column on the far left), we then see a message box that says "Replace the picture with your changes?  Yes, replace the old one!  No, save a new file!"  Regardless of the selection we make, we see the error message noted above.  And, after making the selection, we see no saved file anywhere to open.

Also, the Tools double column on the left does not list any "cache" or such place to even retrieve a saved file.  The bottom two tools are "Print" and "Quit."  What are we doing wrong here?  She needs to get something saved to a thumb drive by tomorrow night (it is now Sunday, January 24), and we have been unable to get this done.  Thanks.