You can definitely install the provider manually. To locate the .msi package, look in the filesystem on the EminentWare server in the following directory (assuming the default install path): C:\program files\eminentware\server\packages\eminentware. In that directory, you'll see a file like wmiproviders_1.40.126.msi. That is the WMI provider and you can move it to wherever and just double-click it to launch the install.
Now, I have no idea if it will run with virtualbox, as I'm not familiar with that. I can tell you that we have a number of clients using VMWare and VPC VMs with no problems.
Just to let you know what I found out about this issue.
Yes it will work on a Ubuntu machine running virtualbox for a windows machine.
However you will need to set your virtualbox up with a bridged network adapter instead of the "Network Address Translation" (NAT) mode which virtualbox uses by default.
for example on my machine I had to setup a bridged adapter on my linux wlan0 adapter. This allows the virtualbox to obtain a true network ip instead of receiving a generic 10.0.*.* address from virtualbox.
My co-worker said he has run into previous issues of Ubuntu not liking the bridged network adapter setup. I am running the most recent version of Ubuntu, and version 3.1.0 r55467 of virtualbox, and it worked the first time I set it up.
Glad to hear that it worked out and thanks for the update. Now I can probably talk someone into letting me get a linux box ;-)