Error running a new process instance

hi,I add a process,and config a script task.When I try to creat a instance,it run fail,and the error messages is “Error in Script”.
This is script content.

<scriptTask id="script" scriptFormat="JavaScript" flowable:autoStoreVariables="false">
    def scriptVar = "test123"
    execution.setVariable("myVar", scriptVar)

What is wrong with this script?

I solve this.Filling the attribute in the Corresponding box,It runs successfully.