I have the exact same problem and yes I am using a Nvidia controller, a nForce 430/6150 Asus A8N-VM CSM motherboard to be exact.
I know its not the media as I am using the same Verbatim DVD+ DL discs I have always used on the same SATA based Pioneer DVD recorder.
This seems to have started happening after upgrading my nForce drivers to the latest ones available on Nvidia.com
Is this a known issue? The discs seem to play fine but it Imgburn always ends with this error when completing a burn.