corrupt table

I'm seeing the following with one of our tables:

  db=> select * from diskmon.vob_usage;
  ERROR:  _mdfd_getrelnfd: cannot open relation vob_usage: No such file or directory

This is running under 7.3.3.  I'm not sure how this occurred.  Is this table
completely trashed or is there something that can done to recover it?

Thanks.

--
Brandon