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.
Davide
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