Have you manually deleted any transport packages?
Is there anything in the MODX error log?
checks the integrity of the transport package records in the DB and can sometimes fix them, though it's not free.
The fact that you see that problem in a fresh install, suggests that that's not the problem, though.
Sometimes the transport packages page takes a very long time to load, so give it plenty of time.
Also, try visiting the site with your browser in incognito or private mode. Sometimes a cookie or something left in the browser cache can mess up some Manager sections.