Exception:"HTML_CONTROL_ERROR"

Dear All,

I have exposed an RFC Function module as a webservice.Inside the FM bsed on Importing paramters i have called a Webdynpro transaction using  CALL TRANSACTION 'ZXXXX' AND SKIP FIRST SCREEN .(I have created a paramter transaction for the WDA Component in SE93). Inside WDA i have generated ITS url and displayed it in an Iframe.

Problem Scenario:When i test this webservice inside SAP GUI manullay this works fine(ITS url works fine) but when i trigger this webservice from BI Dashboards 4.0 it i get dump as follows."Exception condition "HTML_CONTROL_ERROR" raised."

Please suggest.Your help is highly appreciated.

Thanks
Prabaharan