Taken from the WHDLoad FAQ ...
"Especially a 68040/060 CPU or some turboboards/other hardware may cause problems. Try to turn off all extra hardware and try to start the install again"
Maybe WHDLoad just doesn't like your '040's. Using the latest version of WHDLoad, yes?
Also try running WHDLoad from the CLI and see what error message it returns (if any). It may help to narrow down the problem.
