11.04 Server amd64 Install ISO fails at Installing base system

[Juvenal1228]

roughly 90% into the "Install base system" step on the 11.04 server amd64 CD installer it will ask the user to insert the cd labeled
'Ubuntu-Server 11.04 _Natty Narwhal_ - Release amd64'
where the CD image downloaded from the ubuntu project is labeled
'Ubuntu-Server 11.04 "Natty Narwhal" - Release amd64'

no matter what is done this prompt will not go away and halts the install process.

I was able to install 11.04 server using the mini cd image

[Andrey (aol-nnov)]

the same thing here!

interesting parts of syslog follows:
Jun 24 16:28:11 base-installer: W: Skipping nonexistent file /media/cdrom/dists/natty/main/binary-i386/Packages
Jun 24 16:28:11 base-installer: W: Skipping nonexistent file /media/cdrom/dists/natty/main/debian-installer/binary-i386/Packages
Jun 24 16:28:11 base-installer: W: Skipping nonexistent file /media/cdrom/dists/natty/restricted/binary-i386/Packages
Jun 24 16:28:11 base-installer: W: Skipping nonexistent file /media/cdrom/dists/natty/restricted/debian-installer/binary-i386/Packages

there are Packages files, but they're gzipped.

any glue?
Thanks!