OK. Remove chain. Does wheel turn freely in the dropouts ? Is chain too tight like Mumonkan asks ? Take a side view pic on the drive side. I have a Wabi wheel, and I can't see how the freewheel can be the problem.

Edit: I posted this before your above post with the hub pics, and your hub looks totally different than mine, so maybe Wabi made a change to the hub that is causing the problem. I can see the issue, and you definitely need to resolve it with Richard.

Edit 2: I looked on the Wabi website and indeed the dust cover design has changed since I bought my new generation Wabi wheels that have the bolt-on design and are fixed-fixed. The dust covers are smaller on mine and clear the freewheel body where it tapers down past the threads. You may be able to fix this by placing a thin shim between the hub flange and the freewheel.