It's connected through a 3 mtr long USB cable with a "Mac Mini" which is placed at the attic (along with a NAS, rfxcom LanTransceiver, Gigabit Shwich, Gigabit Wlan router).

Having the Z-stick like this is not really nice looking (for WAF reasons ) and is also not preferred for safety reasons as well (don't want to help burglars to much).
So I tried to get working with the stick straight into the MacMini placed at the attic. That's not working (might be because the RFXCOM and Wlan are to near?). Then I tried to move it a bit further away form the RFX and Wlan (also on the attic) did not help. Next I tried it with placing a spare z-wave Switch somewhere on the attic to improve the mesh network. Did not help a bit! Having it working with Homeseer I tried to optimise the network several times on a row but that did not help.
So, I ended up with a usb cable an dongle hanging out in the office (moving it closer to the wall or more against the roof, also meshes up the working).
So what did you do to have the Z-wave dongle working properly, without having it in a not so nice place like this?
Any ideas how to improve my set-up (preferably having it placed at the attic)?
Thanks.
Wiechert
My set-up: MacMini (Parallels VM, windows 7) HomeseerPro, RFXCOM Lan Transceiver, Aeon-labs Z Stick2