I am just trying to learn DSL and have immediately run into issues. I have a simple DSL in the file named XEasyApp.dsl : *[condition][]{value} is an invalid Boolean={value} not in("T","t","1","F","f","0")* and then a simple DSLR in the file named Test.dslr: * package com.onfs.easyapp.rules import com.onfs.easyapp.EasyApp expander XEasyApp.dsl rule "EasyApp Insured is Citizen Validation" when $ea : EasyApp(priIns_eaInsuredIsCitizenInd is an invalid Boolean) then $ea.addError(drools.getRule().getName()); end* I get the expected expansion in the DRL Viewer: package com.onfs.easyapp.rules import com.onfs.easyapp.EasyApp rule "EasyApp Insured is Citizen Validation" when $ea : EasyApp(priIns_eaInsuredIsCitizenInd not in("T","t","1","F","f","0")) then $ea.addError(drools.getRule().getName()); end There are no Red X's when I view Test.dslr in the editor, however a problem shows up in the Problems area below: *Description Resource Path Location Type [13] Unable to expand: $ea.addError(drools.getRule().getName()); Test.dslr /TermXpressRules/src/main/rules Unknown Drools Error*