I've a problem booting BT5 64Bit Gnome ('I've tried also KDE).

douring startup i read this message:

Code:
grep: /root/cdrom/preseed.seed : No such file or directory
Done.
I don't know if it's an error.

Some lines below:
Code:
Using CD-ROM mount point /cdrom/
Identifying.. [28f5ebfc7c66fa22508cc904e1dc6e70-2]
Scanning disk for files..
Found 1 package indexes, 0 source indexes, 0 translation indexes and 0 signatures
Found 1 package indexes, 0 source indexes, 0 translation indexes and 0 signature
There I can't type anything and the boot stops.
If I press "ESC" appear the splashscreen of BT5, but nothingelse

Can some one help me?
I've tried the same cd on another PC and it worked fine!