VPC and Internet (again)

I get an error message upon launching VirtualPC when I try to launch
Internet Explorer:

"Virtual Switch networking could not be started.
Permissions for the support files were set correctly, but Virtual
Switch failed to load. Please report this problem to Microsoft (Code
A1004). Virtual PC will run without Virtual Switch networking."

I gather from some others posts (http://groups.google.com/group/
microsoft.public.mac.virtualpc/browse_frm/thread/
0b11aa79411a80e4/53bf860bdfea7de4#53bf860bdfea7de4)
that someone is able to get a connection, but the problem doesn't
seem to be the same (?).

Anyone know how to work around this?

Thanks,

Torsten