Niall Mansfield has developed a patch to the current version of the fancyvrb package, and submitted it to me (as a conduit to ctan).
The patch addresses a bug in the code related to selecting lines for verbatim printing: if first selected line == last selected line (i.e., only one line was to be printed), the package failed.
The new version has been installed at cambridge ctan, and should be on its way around the world.
Users may view the package's catalogue entry at: http://www.tex.ac.uk/tex-archive/help/Catalogue/entries/fancyvrb.html or browse the package directory tree: http://www.tex.ac.uk/tex-archive/macros/latex/contrib/fancyvrb/
The catalogue entry will be (modestly) updated on the web, overnight.
Robin Fairbairns
For the CTAN team