How can I use Oracle's virtualbox listpartitions command on Windows 7

I'm using Oracle's VirtualBox (4.2.6r82870) on Windows 7 and I'm trying to list the partitions on my uSD card which is inserted in the computer as drive "E". I pulled open the Window's Computer Management->Disk Management window and I can see E is mounted as "Disk 1"

So initially I tried this command:

C:\Program Files\Oracle\VirtualBox>VBoxManage.exe internalcommands listpartitions -rawdisk \\.\PhysicalDrive1

but I got back an error:

VBoxManage.exe: error: Cannot open the raw disk: VERR_ACCESS_DENIED

I read this was because I couldn't use this feature unless I was running as admin, so I found the VBoxManage.exe program, right clicked on it and selected Properties->Compatibility and picked to "Run this program as an administrator".

Now when I issue the same command it sits there for awhile then spits back:

VBoxManage.exe: error: Failed to create the VirtualBox object!
VBoxManage.exe: error: Code CO_E_SERVER_EXEC_FAILURE (0x80080005) - Server execution failed (extended info not available)
VBoxManage.exe: error: Most likely, the VirtualBox COM server is not running or failed to start.

What is the proper way to get this program to run correctly?