So the problem ended up not being RHEL or CentOS and is totally a bug in 3.7.4 related to class library population on game launch. To fix it without the update I'm rolling now, just open the Rules Library and navigate to the class library (last tap on the right). Open and close a class. Oh, and just to be 100% clear, if you were running beta version of the application 3.7.3.x it's quiet possible you've got class definitions that need to be cleared out! if so, the class definitions here will be incomplete (3 - 5 lintes). Just purge the whole list then open Options->Network and click on Refresh Resources to import the classes.txt defs into the library. Now when folks connect it'll be correct! 3.7.5 is being rolled with a fix for the on-load bug, however, this will not auto-correct beta builds which have incomplete class imports.