Hi I'm using fedora 3, I'm trying to burn a 4.4GB tar.bz2 file on a dvd but didn't work, here's my output.
Linux server2 2.6.12-1.1381_FC3 #1 Fri Oct 21 03:46:55 EDT 2005 i686 i686 i386 GNU/Linux


[root@server2 tmp]# cdrecord -dao backup-20060304-140619.tar.bz2
Using libscg version 'schily-0.8'.
cdrecord: Warning: using inofficial libscg transport code version (schily - Red Hat-scsi-linux-sg.c-1.83-RH '@(#)scsi-linux-sg.c 1.83 04/05/20 Copyright 1997 J. Schilling').
Device type : Removable CD-ROM
Version : 0
Response Format: 2
Capabilities :
Vendor_info : 'HL-DT-ST'
Identifikation : 'DVDRAM GSA-4163B'
Revision : 'A103'
Device seems to be: Generic mmc2 DVD-R/DVD-RW.
cdrecord: Found DVD media: using cdr_mdvd.
Using generic SCSI-3/mmc DVD-R(W) driver (mmc_mdvd).
Driver flags : SWABAUDIO BURNFREE
Supported modes: PACKET SAO
scsi_set_streaming
Speed set to 2770 KB/s
Starting to write CD/DVD at speed 2.0 in real SAO mode for single session.
Last chance to quit, starting real write 0 seconds. Operation starts.
trackno=0
Turning BURN-Free off
cdrecord: Turning BURN-Free on
cdrecord: WARNING: Drive returns wrong startsec (0) using -150
cdrecord: Input/output error. write_g1: scsi sendcmd: cmd timeout after 0.000 (200) s
CDB: 2A 00 00 00 62 35 00 00 1F 00
Sense Bytes:
Sense Key: 0xFFFFFFFF [], Segment 0
Sense Code: 0x00 Qual 0x00 (no additional sense information) Fru 0x0
Sense flags: Blk 0 (not valid)
resid: 63488
cmd finished after 0.000s timeout 200s
write track data: error after 51488768 bytes
cdrecord: A write error occured.
cdrecord: Please properly read the error message above.
cdrecord: Success. flush cache: scsi sendcmd: no error
CDB: 35 00 00 00 00 00 00 00 00 00
status: 0x2 (CHECK CONDITION)
Sense Bytes: 70 00 04 00 00 00 00 10 44 8D BB 0D A0 80 00 00
Sense Key: 0x4 Hardware Error, Segment 0
Sense Code: 0xA0 Qual 0x80 (vendor unique sense code 0xA0) [No matching qualifier] Fru 0x0
Sense flags: Blk 0 (not valid)
cmd finished after 3.579s timeout 1000s
Trouble flushing the cache
[root@server2 tmp]#

What am I doing wrong?

Use growisofs not cdrecord, and 4.4-GB just might be bit to large....

Example; growisofs -Z -dvd-compat /dev/scd0 -R -J /some/files

Hint: ls -l /dev/cdrom

Quoting from; http://fy.chalmers.se/~appro/linux/DVD+RW/

And once again, do keep in mind that 4.7GB are salesman's GB, i.e. 1000^3 and not 1024^3. If translated to "real" GB, DVD±R[W] capacity is not larger than 4.4GB! It should also be noted that earlier growisofs versions did not check if there is enough space on media to accommodate the data set to be burned, meaning that it was your sole responsibility to make sure "overburn" condition is not raised. As of version 5.2 growisofs performs the necessary checks for you and refuses to start recording if "overburn" condition appears to be unavoidable. This behaviour can be overridden with -overburn command-line option.

What about other possible solutions to dvd? I want to backup my files to multiple DVD's, I have around let's say 15GB of data to backup. So I need some script which supports resuming, now I found some programs (dvd_backup,multicd-1.7.5,sync2cd-0.9) But I didn't have success, multicd seems really good but it uses cdrecord, and it doesn't work (I don't know how to get it to work, it gives an error while trying to write) The program itself is really cool, it starts writing and tells you to put another empty cd to continue etc. But I don't know how to use cdrecord for dvds. So, what would you suggest as a backup solution to dvds?

Look at dar for this:
http://dar.linux.free.fr/
There should be a prebuilt package (rpm, deb,...) on almost all distributions so you don't need to compile it yourself.