Colour Profiling?

OK, so I am trying to calibrate my Epson P50 (with continuous ink system) with my mac... I use PSE 6 for mac, and RGB colour space. The colours the printer is giving me are way off - my black and white photos are coming out with a god-awful purple tint.

I have printed alot of photos from DS colour labs, and never have any issues with colour matching, so what can I do to get my printer matching everything else?

Argh!