Do you mean "JavaScript", or do you mean "Java scripting"? If you mean "JavaScript", then Ulrich's response is valid. If you mean "Java scripting", and you're actually using BeanShell in your scripted assertion, then make sure your "return" lines don't use capital letters.
Or, you could use one of the built-in assertions instead of a scripted assertion. "Ensure properties are equal" is the same as the one you've shown in your script snippet. You can add multiple assertions to a step to cope with your multiple match criteria requirements.