Problem while burning with my eMac

I've got my Emac for a little more than one year and now I can't burn CD anymore
I don't understand beacause I burned less 15 CD. It's very cheap
It's strange, because my combo can read CD or DVD but not burning.
And the Hardware Test didn't found any errors :-/
Informations about my combo are:
Fabricant:     HL-DT-ST
Modèle:     HL-DT-ST RW/DVD GCC-4481B
Révision:     2.05
Numéro de série:     
Type de disque:     CD-RW/DVD-ROM
Gravure du disque:     Géré/Livré par Apple
Support amovible:     Oui
Disque amovible:     Non
Protocole:     ATAPI
Numéro de l’unité:     0
Type de socket:     Interne
I read some thing about firmware but where can I find it ? Apple don't provide it and didn't say anything about this problem... It is not fun


I too am having trouble with burning...It tries to burn then I get an error, communication to the drive failed, so it won't burn and disk can no longer be used.
What could be causing this. I'm obviously not the only one with burning problems, but I don't like that I can't burn, therefore cannot make backups of my files. This is bad.
Please can anyone help?