I'm trying to copy a movie DVD on a machine with a single DVD-R drive. After the program copies the original DVD, it ejects the DVD and prompts me to insert a blank DVD -- so far, so good. However, when I insert a blank DVD, the software makes no attempt to write to it, even though it "found" the blank DVD in the drive.

KDE 4.7.4
K3b 2.0.2
Pioneer BDC-202 BD-ROM DVD/CD-R

Disregard.

I mistakenly put a standard DVD-R in the drive (not enough capacity) and the not dual-layer DVR+R I needed. Would have been nice to get an error message stating the DVD-R wasn't big enough.

You may want to file a feature request / bug report at bugs.kde.org regarding that as it should ask you to change the medium to one of an appropriate size for the job you are trying to complete.