Error message when upgrading Galaxy S to Froyo-Collection of common programming errors

So I finaly got a copy of Windows and installed VMWare on OS X After fidling with driver issues etc. etc. I got the Kies software to recognize the Gallaxy S

After Kies had downloaded the upgrade files and started (an image of the Android raking leaves on the phone screen) this message pops up

“failed to convert to upgrade mode”

Does anyone know what the problem is? and how to get around this?