K3B Not Recognising CDR

Hi,

I have searched the forums, but for some reason K3B is not recognising the blank CD placed into the drive when i select BURN, yet it does display the CD-R detrails - empty, space etc. in the relevant window.

As such how do i allow the K3B program to burn the files - error message is "Please insert a suitable medium".

Thanks and regards,

Richard.