Reply to Pre-listening issue Traktor 2 & VCI100

Hi All,

Having an issue with the pre-listening function. I tried plenty of things but it is just not working.

Set up: Easy
- Traktor 2 with final DJTT mapping for VCI-100
- A Numark DJio soundcard / A Presonus VSL 22 (tried with both souncards seperately but not working on either of them)
- Macbook
- VCI100

Everything is working perfectly except the pre-listening.
Traktor is responsive when I touch the buton on the VCI and turns blue. The level for headphones is up. This exact same configuration use to worked on my previous PC (in order to see if that was coming from the mac, I tried again on the PC: not working!), the mapping is the one provided by DJTT so it is ok ...

I just can't get my head around this...

Is the controller broken inside? If so, how come Traktor is responsive to it?
Issue with the ext sound card? If so, why was it working before & not working today on 2 different cards
Mapping? Maybe... but just installed the final DJTT mapping...
==>

If anybody could look at this under a different angle and help me out, that would be very much appreciated!

Hope you guys can help!

Cheers