Based on the error message, it sounds like you tried to run port clam. That's not a valid MacPorts command.
It also looks like you tried to run sudo port load clamav. Instead, you should install the clamav-server port and then follow the instructions in the notes it prints, or review those notes at any time by running port notes clamav-server.
In the general case, you can find out what files a port has installed by running port contents followed by the port name, for example port contents chkrootkit.
If you need further help using MacPorts, please write to the macports-users mailing list, rather than writing in the issue tracker. The issue tracker is for bug reports and feature requests.
