BizTalk Error: Value was either too large or too small for an Int32

SYMPTOMS The error message appears when you use BizTalk’s Cumulative Functoids. —————————————– Error Details: “error btm1050: XSL transform error: Unable to write output instance to the following <file:///C:\…..\Map1_output.xml>. Function ‘userCSharp:MyConcat()’ has failed. Value was either too large or too small for an Int32.” This problem may occur when the Cumulative Functoid accept a Null input…