I've just uploaded a new build of ArtRage to the member area.
The following bugs have been fixed:
1) Watercolour sped up again! Sorry about breaking that.
2) Crash on deleting actions. I think I've pinned that one down.
3) Crash on changing Retina support in ArtRage preferences.
4) Load texture map button in the custom brush designer is now working.

The ArtRage website has also been updated so downloading the demo version now correctly downloads the ArtRage 6 demo instead of the ArtRage 5.