selfupdate fails

[ali_kaylan@…]

after installing the software with the finder and executing:

sudo port -d selfupdate

installation fails with:

[ ! -f /opt/local/etc/macports/mp_version ]

rm -vf /opt/local/etc/macports/mp_version

===> making install in doc /usr/bin/install -c -d -o root -g 501 -m 755 /opt/local /usr/bin/install -c -d -o root -g 501 -m 755 /opt/local/etc/macports cat prefix.mtree | /usr/sbin/mtree -U -e -p /opt/local > /dev/null mtree: line 6: unknown group 501 make[1]: * [install] Error 1 make: * [install] Error 1