Using Any of the recent CVS builds, with Direct3D output, selecting the HQ2X shader, I get this error:
hq2x.fx(196): errorX3004 undeclared identifier 'WorkingSampler1'
D3D:Pixel shader output disabled

I would really love to figure out why it's doing this, and fix it. But I know nothing about pixelshaders and all this newfangled stuff. Other shaders work fine.

Any ideas?