From bug: 251576: "For packages without any files the callback is "emulated" on install, but not on erase at the moment." It causes the problem of the transaction callback in python not being able to run what it said it was going to run.
Fixed in next rawhide push by rpm 4.4.2.2-rc2
rpm-4.4.2.2-2.fc7 has been pushed to the Fedora 7 testing repository. If problems still persist, please make note of it in this bug report. If you want to test the update, you can install it with su -c 'yum --enablerepo=updates-testing update rpm'
rpm-4.4.2.2-2.fc7 has been pushed to the Fedora 7 stable repository. If problems still persist, please make note of it in this bug report.