Problem with my CD/DVD drive

i recently had a dell engineer come fit a new HL-DT-ST DVD+-RW GSA-H53N drive into my Dimension 3100.

Now the drive, reads any type of disc perfectly, it works fine...

just when i go to actually write files, mp3s or anything onto a disc, it wont work...

does anyone know what the problem could be?...is it something to do with the firmware

thanks