the request has missing or invalid parameters

 HI
I know this has been reported on frequently but I haven't found the answer yet
I tried the OpenCalais Webservice and it worked about 10 times, but since then i get the response
 
 faultDetail: 
{}:return code:  403
Invalid request format - the request has missing or invalid parameters
{http://xml.apache.org/axis/}HttpErrorCode:403
when calling
 
String result = new CalaisLocator().getcalaisSoap().enlighten(licenseID, "Ernest Hemingway", paramsXML);
license ID is correct cause it worked before and I took the paramsXML String from the example page.
Any idea what I could do?
 
cheers,
felix