Wing's CVS support requires the cvs command line executable to be installed separately from Wing. Please see http://www.nongnu.org/cvs/ for information about CVS. The cvs executable may either be in your path or set it with the CVS executable preference in the Version Control / CVS preferences group.
The CVS support works best if usernames and passwords are handled by another program such as ssh-agent, pageant, or another ssh agent. For details on this see Setting up SSH.
If this is not possible and you must use the obsolete pserver authentication mechanism, you will need to issue the cvs login command once from the command line before starting Wing.
CVS defines the following commands, in addition to those documented in Common Version Control Operations:
This operation will dispose of any local changes and revert the local files to match the current revision in the repository.