[rules-users] Unable to create Field Extractor

Hi, I'm using JBoss Rules 4.0.7 and I having this error when executing some rules. org.drools.RuntimeDroolsException: org.drools.RuntimeDroolsException: java.lang.IllegalStateException: Error in getting field access method.Unableto create Field Extractor for 'codigoPlan' of '[ClassObjectType class=com.sample.Afiliado]' The Afiliado class has a getCodigoPlan() public getter to a codigoPlan field. The rule is: rule when socio : Afiliado( $codigoPlan: codigoPlan != null ); then System.out.println( $codigoPlan ); end I check the manuals and mail lists and everyone has issues with getters. That's no my case I think. Any ideas of what's happen ? Regards, -- Hugo