Hi wbs_dan: Thank you very much for contacting the Intel® NUC communities. We will do our best to try to fix this problem.
In regard to your inquiry, when you use adapters or converters it is not guarantee that they will work for sure, we normally recommend to use a high quality cable or an active adapter in order to make it work, but it is not for sure.
Just for testing purposes to rule out a possible problem with the NUC itself, do you have the option to test the NUC using the HDMI straight connection with an HDMI monitor?
On the following link you will see a list of tested peripherals that Intel validated as fully compatible with the NUC, in there you will see some HDMI to DVI adapters and cables:
Any further questions, please let me know.