There shouldn't be anything specific with root permissions needed.
Two things to check:
1) There is a known defect that when you log into the web client, the VDP appliance will not show up the first time. If you log out and back in, the VDP appliance will show up the 2nd time.
2) If the above is not applicable, then in a browser, go to https://<vCenter_IP>/mob
3) Click on content hyperlink
4) Click on ExtensionManager hyperlink
5) Check to see if the Extension "com.vmware.vdp" shows.
If the Extension does not show, then it is a permissions issue we need to figure out, as the VDP appliance did not install properly.
If it is showing, then we would need to look at logs, which means a VMware support case would most likely be required.