I've found the source of the error, but still can't get the rule right.
When I apply the behavior to the page, I notice in the code it's placing the HTM: markup for quotes around the rule name in the IF statement
This also causes and error when I go to open the show Region dialog from the Server Behaviors panel - it says that the rule is no longer defined. So I change the markup to just regular quote symbols and all those errors go away. This does not happen when using Page Access. I'm using DWCS 4 on windows, and Sec Assist 1.1.9.
Is this a bug or a setting or just some random outcome because of a convergence of different things? Either way, it's not a big deal to work around, I'd still like to be ale to get my rule properly defined.