return <blank> tag

hi
through my stored procedure i m returning such a string

Code:

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SET @vsResult = 'SUPPLIER CODE / ' + ISNULL(CONVERT(VARCHAR,@vnSupplierID),'<BLANK>')
 SET @vsResult = @vsResult + ' ' + 'PRODUCT CODE / ' + ISNULL(CONVERT(VARCHAR,@vsProductCode),'<BLANK>')
 SET @vsResult = @vsResult + ' ' +'GL CATEGORY CODES / ' + ISNULL(CONVERT(VARCHAR,@vsGLCategoryCode),'<BLANK>')
 SET @vsResult = @vsResult + ' ' + 'RESULT: '

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in my procedure its returning string as i expected.but problem is in my vb it does not showing <BLANK> TAG.

Code:

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With mobjDatabaseReader
                    .SPRun msMsgStoreConnection, _
                    SP_BULKIMPORT_PRODUCTGLCATEGORYDATA, _
                    .MakeParameter("@vnMemberID", adtInteger, apdParamInput, , vlSender), _
                    .MakeParameter("@vnSupplierID", adtInteger, apdParamInput, , asLineCols(lCount, 0)), _
                    .MakeParameter("@vsProductCode", adtVarChar, apdParamInput, 50, asLineCols(lCount, 1)), _
                    .MakeParameter("@vnIsStock", adtInteger, apdParamInput, , IIf(asLineCols(lCount, 2) = "Y", 1, 0)), _
                    .MakeParameter("@vsGLCategoryCode", adtVarChar, apdParamInput, 1000, asLineCols(lCount, 3)), _
                    .MakeParameter("@rsResult", adtVarChar, apdParamOutput, 1000), _
                    vsResult
                End With

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what could be problem.
thanks