strange error in /var/log/messages

[Luigi Curzi <luigi_curzi@yahoo.it>]

when i log in kde (3.4 downloaded in alioth, but i think that i have
same problem with version in debian sid) appears this error in
/var/log/messages:

May 17 12:36:43 vucinet kernel: hdc: drive_cmd: status=0x51 { DriveReady
SeekComplete Error } 
May 17 12:36:43 vucinet kernel: hdc: drive_cmd:
error=0x04 { AbortedCommand } 
May 17 12:36:43 vucinet kernel: ide: failed opcode was: 0xe5 
May 17 12:36:43 vucinet kernel: hdc: drive_cmd:
status=0x51 { DriveReady SeekComplete Error } 
May 17 12:36:43 vucinet
kernel: hdc: drive_cmd: error=0x04 { AbortedCommand } 
May 17 12:36:43 vucinet kernel: ide: failed opcode was: 0x98 
May 17 12:36:43 vucinet
kernel: hdc: drive_cmd: status=0x51 { DriveReady SeekComplete Error }
May 17 12:36:43 vucinet kernel: hdc: drive_cmd: error=0x04 {
AbortedCommand } 
May 17 12:36:43 vucinet kernel: ide: failed opcode was:
0xb0

hdc is a dvd burner (ide). it happens with any kernel of 2.6.x series,
unless that i use scsi-emulation.
i thought that it depended on kernel configuration, but if i remain in
console, or if i don't log in kde, but X is started, error doesn't
appear.
moreover, if i try to burn a dvd/cd (in kde) velocity of process is slow
(0.4x for a dvd-rw 2x) but, if i uninstall ide-cd module and i
re-install it, velocity is good.

i'm very confused!?!?!?

thanks in advice
Luigi