Hi,
I just installed "dia" and got this error:
Installation...cp: cannot overwrite directory `/usr/share/pixmaps' with non-directory
Upon inspection it turns out the fs/usr/share/pixmaps file in the archive is the png icon itself. Looks like the receipt command "cp -a $install/usr/share/icons/hicolor/16x16/apps/dia.png $fs/usr/share/pixmaps" in genpkg_rules() found no target dir, so renamed "dia.png" as "pixmaps"! So maybe add $fs/usr/share/pixmaps to the mkdir command?
HTH