Custom Exception Message Using Out of the box Exception in IBM BPM

to  catch exception using out of the box intermediate event  get the message from tw.system.error using the following Xpath expression

tw.local.error=tw.system.error.xpath("/error/localizedMessage").item(0).getText();

and here is the output

and here is the used human service to demonstrate this in the sql service i tried to access www table which is not in the Database