Unable to invoke CFC - The DATA parameter to the addMarginOrRefund function is required but was not

Im calling a remote object like so to the server

private function addMarginOrRefund(event:MarginCall_or_Refund_Event):void
            {
                myService.addMarginOrRefund(event.data);// cf calls a sp
            }

CF

<cffunction name="addMarginOrRefund" access="remote" returntype="void">
  <cfargument name="data" type="Any" required="yes">

    <cfquery name="q" datasource="#datasource#">   
                       
                       
                        INSERT INTO [tb_MarginCall_or_refund]
           ([clientID]
           ,[dealerID]
           ,[isMarginCall]
           ,[currency]
           ,[amount]
           ,[dateRequested])
     VALUES
           (
<cfqueryparam value="#arguments.data.clientID#" cfsqltype="cf_sql_integer">,
<cfqueryparam value="#arguments.data.clientID#" cfsqltype="cf_sql_integer">,
<cfqueryparam value="#arguments.data.isMarginCall#" cfsqltype="cf_sql_bit">,
<cfqueryparam value="#arguments.data.currency#" cfsqltype="cf_sql_varchar">,
<cfqueryparam value="#arguments.data.amount#" cfsqltype="cf_sql_numeric">,
<cfqueryparam value="#arguments.data.date#" cfsqltype="cf_sql_date">,
              
                       
                        </cfquery>

</cffunction>

but I get an fault on the flex side

faultCode:Server.Processing faultString:'Unable to invoke CFC - The DATA parameter to the addMarginOrRefund function is required but was not passed in.' faultDetail:''

not sure why I should get this, any help would be appreciated