There is an error in the V0.3.4 desktop versions (Linux, OSX, Windows) that prevents the USB connection to work.
Download and unpack the V0.3.4_fix archive into the V0.3.4 folder and overwrite the qDslrDashboard executable.

In case of the OSX redownload it again.

qDslrDashboard V0.3.4 is now available with the following changes

• added BULB capture for Sony cameras that support it (needs the latest ‘Smart remote‘ on camera)
• added custom bracketing for Sony cameras (A and M mode)
• added Lumix GH4 (and probably other Lumix models that support PTP mode) USB connection (their PTP implementation is very basic, capture, change shutter/aperture/iso, browse/download images)
• other fixes reported by users

I wish you all Merry Christmas and a Happy New Year.