The Web Server that comes with the Internet Toolkit is a G Web Server. You can run the LabView Web Server emmbedded in an RT Target, but not the G Web Server.
Have a look at the LabView RT User Manual (page 1-6 for the 7.1 release):
http://digital.ni.com/manuals.nsf/websearch/B24A54B2411CF9FC86256E40005C0673?OpenDocument&node=132090_US
For more information what toolsets are supported by LV RT:
http://digital.ni.com/public.nsf/websearch/E661C67934D5AB4A86256B800055DA75?OpenDocument