Error 209 Ambiguous Column Name ...Transaction Count After EXECUTE Indicates That A COMMIT Or ROLLBACK ....

i'm getting following exception when i try to execute stored procedure.
{"Ambiguous column name 'MemberID'.
Transaction count after EXECUTE indicates that a COMMIT or ROLLBACK TRANSACTION statement is missing. Previous count = 0, current count = 1." }
I know why i'm getting "Ambiguous column name 'MemberID'" exception but i dont know why i'm getting
"Transaction count after EXECUTE indicates that......"
In my stored proc i'm checking if error occured goto :Error_handler where i do ROLLBACK TRAN
/* Its failing at    MemberID = tTempResult.MemberID   bcoz of Ambiguous column name. I know i have to use RebateInstanceItem.MemberID=tTempResult.MemberID    */   
here is my stored proc
CREATE PROCEDURE dbo.ExportFile
   @intMonth INT,
   @intYear INT,
   @dtFirstDayOfMonth DATETIME
AS 
BEGIN
BEGIN TRANSACTION

  /*
   I have some logic here that will select rows into temporary table
   #TEMPRESULT
  */
 
   UPDATE
   dbo.RebateInstanceItem
  SET  
   ResubmitCreated = @dtmNewCreated
  FROM #TEMPRESULT tTempResult
  WHERE 
   MemberID = tTempResult.MemberID   
    AND RebateInstanceItem.IsResubmit = 'Y'
    AND (RebateInstanceItem.ResubmitCreated = @dtmLastCreated
   OR RebateInstanceItem.ResubmitCreated IS NULL)    
  IF @@ERROR<>0
    GOTO ERR_HANDLER // when error it will goto error_handler that will rollback
  DROP TABLE #TEMPRESULT
  IF @@ERROR<>0
   GOTO ERR_HANDLER
COMMIT TRANSACTION
RETURN 0
END
ERR_HANDLER:
 ROLLBACK TRANSACTION
 RETURN 1
GO