In particular, check that you have a current version of pg/macros/contextInequalities.pl. This is the file that defines Inequalities::common. But since it also defined Inequalities::Set, I don't see why you would be having this problem. See if an update helps, and if not, delete contextInequalies.pl and update again to get a fresh copy (just to make sure you have not got a damaged copy). Restarting the server should not be necessary for this because this is not one of the cached files, but it never hurts to be sure everything is clean.
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