QTR-Quadtone RIP

I have an Epson 1400 with Cone inks, print on Hahnemuhle Photo Rag, using QTR on a Mac Pro with plenty of RAM running Leopard OS. FWIW, I do imaging in Photoshop CS4 and print using PS CS2. 

Lately I have been reprinting images and have very bad posterizing in the quarter tones. Earlier prints didn't exhibit this. My print settings are by the book. This happens with both 16-bit and 8-bit images. I have also tried using Matte and Photo paper settings. Nozzle check and 21-step wedge look good. 

I recently got a ColorMunki and tried calibrating printer to monitor, but it couldn't read the color chart it printed out, so I shelved the attempt. It seems far fetched that my aborted calibration process tweaked the printer profile, but who knows. This is all starting to seem like voodoo to me.

I have a show on Thursday and have no idea how to correct this. Any ideas out there? Also, does anyone have an assessment of running QTR/Cone on the 1400? (i.e. should I junk it?)
thanks,
Steve S.