Help please - my Imac won't see my ergo-v

Hello -

I just bought an Ergo and it works fine with my Macbook Pro. Plug and play both in traktor and virtual DJ. No problems at all.

I have tried to get it to work with my Imac (2011 3.4 ghz Intel Core i7 running 10.7.5, 16 GB Ram), and it doesn't work either with traktor 2 PRO or Virtual DJ. It doesn't see it at all in either program, and when I use traktor setup it just fails. also tried loading the current .tsi file from the Pioneer website.

Does anyone have any ideas why I'm having this problem, or a workaround?? I updated the firmware in the Ergo when I bought it (and it uploaded the firmware from the Imac with no problem - the Imac also powers the ergo without any problem).