Wilbur freezes upon trying to Incise Flow

[AtomicBlastPony]

When I select "Filter>>Erosion>>Incise Flow", Wilbur freezes immediately. The window for setting blur, amount, etc doesn't even appear.
Someone had this issue earlier with a 12k image on a 32-bit OS, but I'm using a 64-bit OS with the latest version of Wilbur and working with a 4096x2048 image so that doesn't seem to be the issue.

[waldronate]

How long did you wait before terminating the process? It often takes up to several minutes for larger surfaces, especially relatively smooth ones.
Also, look at the performance tab to see if one core is running at 100%.
A quick test to see if it's failing everywhere would be to make a 512x512 image (the default size), Filter>>Noise>>Fractal Noise with defaults, Filter>>Fill>>Fill Basins with defaults, then Filter>>Erosion>>Incise Flow with the defaults. On my machine (10600K processor, 32 GB RAM), the dialog comes up within a couple of seconds at 512x512. At 4096x2048, it took a little over two minutes (maybe three, I was out of the room).
Also, make sure that your altitudes are in a reasonable range; sometimes the fill basin algorithm doesn't work particularly well if your altitude are something like in the range of -1 to +1 (scale by 100 or 1000).