Version:           3.3.2 (using KDE 3.3.2,  (3.1))
Compiler:          gcc version 3.3.5 (Debian 1:3.3.5-13)
OS:                Linux (i686) release 2.6.8-2-k7

As a normal user (not root) I insert a cdrom. Then I start the konqueror program. Then I click on the tab Geräte (devices in english I think). Then I click on "CD-ROM (hdg) [/media(cdrom0]". The cdrom is mounted and the content is shown on the right half of the window. 
Then I wynt to see the content of another cdrom. So I rightclick on "CD-ROM (hdg) [/media(cdrom0]" and choose "Laufwerkeinbindung lösen" (umount drive). Then a window pops up and tells me: 
umount: /media/cdrom0: device is busy
umount: /media/cdrom0: device is busy
Please check that the disk is entered correctly.

Its unbelievable! konqueror is grabbing a hold on this device and is not able to release it! I have some strong words for this behavior but this is not the place to utter them!

I have to open a root console and release the hold with 
kill -9 `lsof -t /media/cdrom0`

I hope you will solve this problem soon. 

Regards 

Juergen Katins