but the supplied types were (flex.messaging.io.amf.ASObject) and converted to (null)."

1、错误描述

[RPC Fault faultString="Cannot invoke method 
'saveOrUpdate'.
" faultCode="Server.ResourceUnavailable" 
faultDetail="The expected argument types are 
(com.***.***.model.****) but the 
supplied types were (flex.messaging.io.amf.ASObject) 
and converted to (null)."]

2、错误原因

3、解决办法