K3b I/O error

Hi everyone,
My English is average and I am an inexperienced Debian user (and completely new to here), but I hope I could explain the problem I am experiencing and that someone could help me out:

I am trying to burn a DVD-R from an ISO image (created using "cat" in cmd out of some .I01, .IO2 … files made by DVD shrink in Win XP…) in K3b. I get a "fatal error during recording: I/O error" at 98% of writing data to disc.
The main video is written to the disc and playable though. Just some extras are missing.
Do anyone have an idea of whether this might be connected to the protection of the original DVD from which I took the media, or is there rather a problem with this ISO image I created?? Or, could it be a defective disc? Or anything else?
The problem should not be connected to not enough space in my tmp directory K3b is using, as I have 15GiB there.
I also tried to burn the same ISO with Brasero (on another DVD-R), there was a fatal error too at the end of the burning process - and this time the movie is not playable from the disc. There is just some 900MiB left and the disc is spoiled.

I would just like to have an idea about what the problem might be connected to. If anybody can help, thanks a lot!
Cheers, Jan

It happened again, exactly the same way as before, with a different ISO image. Fatal I/O error at 98% of writing. Only this time, ALL the data are seemingly OK on the disc, including extras. Strange.

I could find absolutely nothing about this issue. I would appreciate if anybody could help. Thank you.

Here is the log from K3b of this last operation:

Burned media ----------------------- DVD-R Sequential Devices ----------------------- PLDS DVD-RW DS8A8SH KL31 (/dev/sr0, CD-R, CD-RW, CD-ROM, DVD-ROM, DVD-R, DVD-RW, DVD-R DL, DVD+R, DVD+RW, DVD+R DL) [DVD-ROM, DVD-R Sequential, DVD-R Dual Layer Sequential, DVD-R Dual Layer Jump, DVD-RAM, DVD-RW Restricted Overwrite, DVD-RW Sequential, DVD+RW, DVD+R, DVD+R Dual Layer, CD-ROM, CD-R, CD-RW] [SAO, TAO, RAW, SAO/R96P, SAO/R96R, RAW/R16, RAW/R96P, RAW/R96R, Restricted Overwrite, Layer Jump] [%7] System ----------------------- K3b Version: 2.0.2 KDE Version: 4.14.2 QT Version: 4.8.6 Kernel: 3.16.0-4-amd64 Used versions ----------------------- growisofs: 7.1 growisofs ----------------------- Executing 'builtin_dd if=/dev/fd/0 of=/dev/sr0 obs=32k seek=0' /dev/sr0: engaging DVD-R DAO upon user request... /dev/sr0: reserving 1939158 blocks /dev/sr0: "Current Write Speed" is 6.1x1352KBps. 196608/3971395584 ( 0.0%) @0.0x, remaining 201 […] 3900964864/3971395584 (98.2%) @5.5x, remaining 0:10 RBU 100.0% UBU 99.1% 3928752128/3971395584 (98.9%) @6.0x, remaining 0:06 RBU 100.0% UBU 99.1% growisofs command: ----------------------- /usr/bin/growisofs -Z /dev/sr0=/dev/fd/0 -use-the-force-luke=notray -use-the-force-luke=tty -use-the-force-luke=4gms -use-the-force-luke=tracksize:1939158 -use-the-force-luke=dao:1939158 -dvd-compat -speed=8 -use-the-force-luke=bufsize:32m