I installed inkscape 0.48.4-0.1 from experimental. This resolved the issue for me. The release notes [1] say "Some major bugs causing crashes when using extensions or the filters editor were fixed."
I would love to see the fix in the next point release. [1] <http://wiki.inkscape.org/wiki/index.php/Release_notes/0.48.4> -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org