Qnet creates the /net directory. Use the following command to make sure that it exists:
$ ls /net
If you don't see any directory, Qnet isn't running. Ideally, the directory should include at least an entry with the name of your machine (i.e., the output of the hostname command). If you're using the Ethernet binding, all other reachable machines are also displayed. For example:
joseph/ eileen/