Segmentation fault

[Andreas Lennartsson]

Does nayone know why this code cause a Segmentation fault on " rv = 
service->SetCookieString(uri, nsnull, "myCookie=yup; path=/");"

Any help appreciated.
Thanks,

Andreas.

nsresult rv = NS_OK;
nsCOMPtr<nsIURI>uri;
(void)NS_NewURI(getter_addRefs(uri), "http://www.blah.com";);
NS_ASSERTION(uri, "malformed uri");

nsCOMPtr<nsCookieService> service = 
do_GetService(NS_COOKIESERVICE_CONTRACTID,&rv);
if (NS_SUCCEEDED(rtv)) {
       rv = service->SetCookieString(uri, nsnull, "myCookie=yup; path=/");
}