I’ve tried to create a data DVD to backup some files. I’ve used K3B as always to write the DVD, and the process finished OK. The weird part started when I tried to read the DVD on the same machine I created it.
I got an error from mount about a wrong file system (the mount has iso9660). Checking dmesg, I found these errors:
Aug 9 01:03:24 desktop kernel: [ 2581.266854] attempt to access beyond end of device
Aug 9 01:03:24 desktop kernel: [ 2581.266854] hdc: rw=0, want=68, limit=4
Aug 9 01:03:24 desktop kernel: [ 2581.266854] isofs_fill_super: bread failed, dev=hdc, iso_blknum=16, block=16
I’ve tried to burn a few more DVD with differest option at K3B, but nothing helps. The funny (or not, depends on your point of view) is that windows and Mac OS X read the DVDs without a problem.
Searching the web, I encountred mostly with hardware problems. I’d be happy to get an advise… I’m guessing the DVD isn’t the problem as the write process went fine.
Free Software Universe 
Sorry for being no help, but you might want to have a look at dvdisaster.net for your dvd backup needs. The author knows his stuff and that little tool just works ™ and doesn’t eat your data.
Actually that is not a linux only problem. I had that issue sometime back as well with my DVDs burnt in win xp, that read fine on all other PCs except mine. Even those same DVDs on same PC (dual boot) in Ubuntu couldn’t be read. But DVDs written through ubuntu on that PC could be read. Then after some time same thing started happening to the DVDs I wrote in Ubuntu as well. After applying thousands of tweaks nothing worked until I discovered that I had installed Nero Linux on ubuntu and after uninstalling it, things got solved in linux but uninstalling nero in windows didn’t solve it. Then I formatted everything and reinstalled ubuntu as well as windows and now everything works fine.
Sorry for the long and curvy reply and sort of a no-solution, but thought of sharing that you are not alone..
Which kernel are you running? I had this problem with 2.6.25 (<.8). The kernel was not recognizing disk sizes on media change anymore. You can check by yourself if /sys/block/sr0/size changes when you insert and mount different media.
http://www.spinics.net/lists/linux-scsi/msg26556.html
This was fixed in 2.6.26 and in 2.6.25.8 by commit d1daeabf0da5bfa1943272ce508e2ba785730bf0.
ftp://ftp.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.25.8
Debian forked cdrkit, and the replacement, genisoimage, has some problems. More info:
http://www.orsomething.info/wiki/index.php?title=HOWTO_Burn_UDF_DVDs_With_Debian_Lenny
if you just create an image in k3b, can you successfully mount that?