Turns out that this was an issue with menu not being fully upgraded before installing the new rxvt
/etc/menu-methods/menu.h had been renamed menu.h.dpkg-new. Renaming it back allowed me to remove rxvt and continue the upgrade. Seems like this is actually a bug in menu, or possibly dpkg? Somehow the order of dependencies was wrong, though it doesn't look like rxvt directly depends on menu. Jacob
