No BOM or BS found in B1 payload, check your BIU xsl

i have created b1POtob1so with the intre gration bisn tool

i got the message from message log . what should i do.

com.sap.b1i.xcellerator.XcelleratorException: XCE001 Nested exception: com.sap.b1i.bizprocessor.BizProcException: BPE001 Nested exception: com.sap.b1i.utilities.UtilException: UTE001 Nested exception: com.sap.engine.lib.xml.util.NestedException: BIDI_Wrapper.xsl exception: No BOM or BS found in B1 payload, check your BIU xsl.

please explain.