It seems that the test fast/js/kde/exception_propagation.html is no longer getting parsed fully (throwing a syntax error on line 395). There is a comment in the file about mozilla also throwing a syntax error there so it might be the correct behavior. Either way, by not successfully parsing this test, it's purpose, to test exception propagation, is not being met.
This test passes for me in Mozilla, so the comment may be no longer correct.
Sam, you recently fixed this in r35984.