I found that when doing an ftp install the install would fail if I did not change the partition information. I had a box setup and decided to install over the top of the partitions on it without changing them and only do a format. Well the installer did error out. I then went back and deleted the partitions and added them back during the Red Hat ftp install and everything worked fine. I have not had a chance to test this again so it may have been a coincidence.
I am betting it was a coincidense. We frequently install machines using the ftp install method without reassigning partitions and have no problems like what you describe. Reopen this bug if you are able to reproduce the error.