Media Check issue with Disc 2 and 3...on fc3

[Kyle]

Hello,

I burned the whole 4 CD set of fc3 and the first time it was burned on 
memorex CD's and the second time on TDK CD's.  The first time disc  2 
and 3 failed on media checks but the md5sums checked out ok.  Second 
time, on TDK CD's, disc 2 and 3 failed too and the md5sums 
matched...Disc 2 would go from 44 percent check straight to 100 percent 
and FAIL.  Disc 3 would fail too in a similar way.  I burned them using 
k3b, cdrecord...I noticed that the file size is not the same as the 
ISO's I downloaded for disc 2 and 3. Also when I choose the "verify 
data" option in k3b, it would fail after the verifying the data. I 
downloaded the whole thing via bitorrent.  I have a very fast  
connection so my bitorrent download of 2.3 gigabytes was done in one 
hour plus 15 mins or so. 

I don't understand why this is happening, I have used padding and I have 
burned at slow speeds.  Oh I am burning onto CD-R's. Any feedback would 
be great.  Should I just buy the set from cheapbytes? Are they good, not 
corrupt CD's?

Death tool: 12 Memorex CD's; 4 TDK CD's....

Kyle