I'm sure this won't help much, but that layout led to my last "recycle bin" board. I don't know if it is the layout, but I built it, and could not get it working. Being the stubborn type, I took the schematic and breadboarded it with new parts. I got it working that way and then I perfed it straight off the breadboard. In other words I didn't do a layout. I just took it part by part from the breadboard and worked out the perf layout as I went.
It works great now.
One thing I did do was put the trim pot on the exterior, as I find it is useful to adjust it depending on the depth of the effect.