This is by far the simplest fix for this.  See patch file.

This patch is what Stefan Krah suggested and I agree unless someone a lot more familiar with the import process can take a look at this and re-factor things so the filename is passed along with the file descriptor so the error can include it.  I tried and each change required other changes in order to get the correct failure and error messages.  I gave up when the tests for non existent file started failing with ']' on the first line.

I can't commit this, so could someone who can take a look at the patch and move this along.