NetConnection.Call.Prohibited

Hi,
    I've just started using openamf in favour of macromedias flash
remoting in the past few days. First of all, good work on getting such a
product out to the open-source community :-D
I had everything working the other day, starting with a simple hello
world passing a few strings back and forth, then using ASTranslator to
pass some value objects around, was quite happy with myself ;-) . But
I've just come back to it today and figured I best change the URL in my
Service constructor, to make sure it works on remotely as well as with
localhost e.g.
 
commonService = new Service(
    "http://somedomain:8080/TestApp/gateway",
    null,
    "flashgateway.FlashGatewayBD",
    null,
    null);
 
And I've started getting the error message
'NetConnection.Call.Prohibited' in macromedia's netconnection debugger
(buggy piece of crap btw ;-( if anyone knows hot to make this thing work
reliably without suddenly dying I'd appreciate an email)
My swf is embedded in a jsp with the following code;
        <object width="396" height="500">
            <param name="allowScriptAccess" value="sameDomain" />
            <param name="movie" value="logon.swf">
            <embed src="flash/logon.swf" width="396" height="500" />
        </object>
 
Googling this message only turns up a couple of results and it appears
to be otherwise undocumented :-/ Do I need to create on of these
crossdomain.xml files ? and if so where should I be putting it? in
'/WEB-INF/' ?
Any help and/or guidance anyone can provide would be grealy appreciated
Cheers
Dave
 
PS