Seems like someone removed root's access on the VIC, you're going to need to go into the VIC with a user with Administrator permissions. The click on your host, go to the Permissions tab and change root back to administrator.
I half remember that there is a way to do this on the console, but I'm having trouble finding it right now.
EDIT: Found the console stuff
Ok, yep you can fix this on the console.
You'll need to edit the file /etc/vmware/hostd/authorization.xml from the console.
You should seen something like this:
<ConfigRoot>
<ACEData id="10">
<ACEDataEntity>ha-folder-root</ACEDataEntity>
<ACEDataId>10</ACEDataId>
<ACEDataIsGroup>false</ACEDataIsGroup>
<ACEDataPropagate>true</ACEDataPropagate>
<ACEDataRoleId>-1</ACEDataRoleId>
<ACEDataUser>root</ACEDataUser>
</ACEData>
<... SNIP Other USERS ... >
<... SNIP Possible custom roles ...>
</ConfigRoot>
The piece you are going to want to change is the "ACEDataRoleId" (-1 is Administrators)
you might have to restart the hostd service with service mgmt-vmware restart after your changes.