Can't read Verbatim 16x DVD-R

[2Dogs]

I have four Verbatim 16x DVD-R blank discs I was hoping to burn to - but neither my S182M nor my H22N can write to them. In Nero, I get the error message that the disks are not writable - despite the fact that the media type, DVD-R and id, MCC 03RG20, have been correctly identified.

Here's the DVD Identifier info screen



Here's the Nero Disc Info screen



Any idea what's going on? The four disks were taken from the top of a friend's 50pk cakebox, and look perfect.