DVD SP burn error codes

I am using DVD SP 4.2.1 to burn Verbatim DVD+R DL blanks. Problems were rare until now. Now I am getting a message "Recording device is reporting

the media error: Write error (0x0C, 0x00) on about 1/2 the disks. Using a Pioneer 110D with latest firmware 1.41. This is not happening with every disc. Have I just run into a bad batch, or has Verbatim changed manufacturers?

Is there a way to test a blank for errors before burning? It would save time, but it would still be a coaster, burned or not.

Thanks in advance.