You are getting a card failed error which indicates that the problem is with your Octane setup, rather than the C4D exporter plugin. (So you've probably posted in the wrong thread, really)
Things to troubleshoot include:
Checking you have the correct version of Octane for your card (you know there is a different build required for 6XX series cards, right?) and ensuring you have the correct GPU+Cuda drivers.
Once you think everything is set up correctly, then I'd suggest downloading the example scenes and loading up the benchmark scene from within octane standalone- if that renders okay then you know your Octane setup is now working.
But if you require further assistance getting your Octane setup working- there's heaps of information already available. Here's a good starting point: viewtopic.php?f=21&t=3664
Once your Octane setup is working properly, you should find the C4D exporter will work fine too!