"unrecognized action" error when trying to use an installed port

[Carrie S. Miller]

I have just installed macports (1.8.1) for snow leopard. I also  
installed xcode, so all of these programs are up to date. When I try  
to install a port (e.g. xmgr), the port installs fine and shows up as  
active when I use "port installed." However, when I try to run it  
using either "port xmgr" or "sudo port xmgr" it returns the error:

unrecognized action "xmgr"

This error occurs when I try to run any port that I've installed. Any  
help would be much appreciated.

Thanks