Vista - The parameter is incorrect on shared folder

Hi,

I've got a virtual machine in Virtual PC 2007 running the Vista
Enterprise Trial VHD. I set up a shared folder. Under the Virtual PC
it shows up as "disconnected network share" (or something to that
effect). I can still open it and browse files. i can copy files from
the shared folder to the the Virtual PC without any problem.

However, if I try to install an application that resides on the shared
folder, without first copying to the "local" drive, I get a "The
parameter is incorrect" error and it doesn't work.

Anyone know what the problem is?

thanks,
T.