Cannot install last two 7.0-snapshots via USB attached CD rom.

Hello
 I am using both a Tyan S2881 and S2882 motherboard with Opteron Processor.
 I have been trying to install the 7.X snapshots for some time now via A USB attached CD rom,
(same as I always have for 5 or 6) but so far it still seems broken.

 I can install the snapshots just fine via ATA interface to the cd unit, but I cannot do so via
the CD unit connected via USB. I can, and always have, however installed 5 and 6 this way.


 It always fails in the same place.

F1
 Write failure transfer! (wrote -1 bytes of 1425408 bytes)
F2
....
 /stand/gunzip : <fd:0>: too many length or distance symbols
 /stand/cpio: premature end of file

Retry:
 Write Failure On Transfer 
 Wrote -1 bytes of 1425408 bytes
 /stand/gunzip <fd:0>: invalid code length set


 Being able to install via USB is very important to me. 
 Might anyone know what could be happening? I can swap the disk with a 6.X disk and it ill install
fine. I also cannot install To a USB attached drive using 7, but I can with 6.


 Thanks!

  Nicole