Hi Eliot.
I am looking at the Cog/cygwinbuild/HowToBuild and looking at the build.win32x86/squeak.VM.ImageFormat format to put it in, and reading the HowToBuild it refers to the CroquetVM.
My guess this is a stack.v3 thing and Cog/cygwinbuild tree needs to go in Flat/build.win32x86/squeak.stack.v3 folder.
Sound about right?
thx.
t