Content is not allowed in prolog

Dear Experts,

I have implemented a scenario using SFTP as sender and FTP as receiver.

A txt file is getting picked from thr SFTP adapter, However in sender SFTP adapter m getting the below exception

com.sap.aii.adapter.xi.routing.routing Exception: Unable to parse xml message payload to extract operation for receiver determination.xml.sax.SAXParse:Exception: Content is not allowed in prolog.

I have implemented this scenario using ICO in SAP PO 7.4 with JAVA Mappings please help me out and how can i do for FCC in SFTP with module or In 7.4 , in SFTP adaptor there direct option of FCC ?

please help he out in this issue

Thanks

Umesh Reddy