Just so you know, I attempted to duplicate your edl frame rate error and could not even get my edl process to work.
How I said that I had tied lots of methods, well, so many that I had no idea how I got the my edl to produce no errors in the end (one day later).
Hours later, I managed to open a Premiere Project from Autosave (from previous day) that showed me how I had rendered and replaced the cinema dng with DNxHD MXF OP1a preset of DNX 45 1080p 29.97 that gives a .mxf file extension. It was that Premiere sequence I produced the edl with and replaced reels in Speedgrade with cinema dng files.
After all the time spent re-creating my edl success, left my efforts to chasing your edl error depleted. I did try exporting the edl from Premiere as 'drop frame' checked and 'drop frame' unchecked and doesn't seem to matter as still produces no errors (with respect to your 2014 edl post).
As I confusingly mention above - Playback base frame rate is 4th - means that I observed Speedgrade had at least 4 places to set frame rate. Playback speed is found at bottom Timeline in the View tab.