Linked Stored Procedure Query in Ensemble 2017.2.1

I  have generated a class using the linked procedure wizard however  I can't get it to work if the  datatype  of one of the parameters is VARCHAR(MAX).  It works fine if I change it to say VARCHAR(500) and  rerun the  stored procedure wizard. 

I get the following  error returned.:

ErrorMsg:   SQLState: (07002) NativeError: [0] Message: [Microsoft][ODBC SQL Server Driver]COUNT field incorrect or syntax error

Can anyone see what I am doing wrong?  I think it is to do with the way I am using the  %Stream.GlobalCharacter?   Any help is much appreciated.

Class generated by linked procedure wizard:

Include %occInclude
/// 
Class dbo.spTIETest [ Not ProcedureBlock ]
{

ClassMethod spTIETest(ObjectName As %String(MAXLEN=200), NamespaceName As %String(MAXLEN=50), CacheVersion As %String(MAXLEN=500), RawData As %Stream.GlobalCharacter) As %Integer [ ProcedureBlock = 1, ReturnResultsets, SqlName = spTIETest, SqlProc ]
{
  if '$isobject($g(%sqlcontext)) s %sqlcontext=##class(%Library.ProcedureContext).%New() s RETURNVALUE=$g(RETURNVALUE)
  s ObjectName=$g(ObjectName)
  s NamespaceName=$g(NamespaceName)
  s CacheVersion=$g(CacheVersion)
  s RawData=$g(RawData)
  s hdbc=$$GetConnection^%apiGTW("TestTIEUserProd")
  if hdbc="" { set %msg=$$$ERROR($$$GTWCConnectionError),%msg=$$GetErrorText^%apiOBJ(%msg) goto setError }
  s QHandle=$zf(-5,%SQLGateway,5,hdbc)
  if QHandle="" { set %msg=$$$ERROR($$$GTWCAllocationError),%msg=$$GetErrorText^%apiOBJ(%msg) goto setError }
  s err=$zf(-5,%SQLGateway,$s(%SQLGateway("-uv"):37,1:3),QHandle,"{?=call dbo.""spTIE_InsertTIE_OBJECT_EXPORT""(?,?,?,?)}")
  i err g getError
  s err=$zf(-5,%SQLGateway,62,QHandle,1,4,1,4,10,0,10)
  s err=$zf(-5,%SQLGateway,62,QHandle,2,1,1,12,200,0,200)
  s err=$zf(-5,%SQLGateway,9,QHandle,$lb(ObjectName),2)
  i err g getError
  s err=$zf(-5,%SQLGateway,62,QHandle,3,1,1,12,50,0,50)
  s err=$zf(-5,%SQLGateway,9,QHandle,$lb(NamespaceName),3)
  i err g getError
  s err=$zf(-5,%SQLGateway,62,QHandle,4,1,1,12,500,0,500)
  s err=$zf(-5,%SQLGateway,9,QHandle,$lb(CacheVersion),4)
  i err g getError
  s err=$zf(-5,%SQLGateway,62,QHandle,5,1,$s(%SQLGateway("-uv")&&$zbitget($zversion(0),1):-8,1:1),12,0,0,-2)
  s err=$zf(-5,%SQLGateway,4,QHandle)
  i err=99 s lerr=$zf(-5,%SQLGateway,55,QHandle) s err=$li(lerr)
  i err=99 s err=$$setStream^%apiGTW(QHandle,RawData,0,1)
  i err g getError
  s %ROWCOUNT=$zf(-5,%SQLGateway,31,QHandle)
  set tConnection = ##class(%Library.SQLGatewayConnection).%New() set tConnection.DLLHandle = %SQLGateway, tConnection.ConnectionHandle = hdbc
  set rrs = ##class(%SQL.Gateway.ODBCResultSet).%New(tConnection,QHandle)
  while $Isobject(rrs) {
    if rrs.%GetMetadata().columnCount do %sqlcontext.AddResultSet(##class(%ResultSet.Static).%New(rrs))
    set rrs = tConnection.getNextResultSet(QHandle)
  }
  s RETURNVALUE=$li($zf(-5,%SQLGateway,22,QHandle,1))
setError ;
  If ($g(%sqlcontext)'=$$$NULLOREF) {
    Set %sqlcontext.%SQLCODE = $g(err)
    Set %sqlcontext.%Message = $g(%msg)
    Set %sqlcontext.%ROWCOUNT = $g(%ROWCOUNT)
    w "ErrorMsg: "_%sqlcontext.%Message,!
  }
  s err=$zf(-5,%SQLGateway,16,QHandle)
  QUIT $g(RETURNVALUE)
getError ;
  set %msg=$li($zf(-5,%SQLGateway,12,hdbc,QHandle)) goto setError
}

}

Code I am using to call the  method from  terminal:

  Set OBJECT = "UHSM.LPI.LinkedTable.LPIGPPractice"
  Set NAMESPACE = "WYTTEST"
  Set CACHEVERSION = "Cache for Windows (x86-64) 2017.2.1 (Build 801U) Wed Dec 6 2017 09:07:51 EST"
  Set RAWDATA = ##class(%Stream.GlobalCharacter).%New()
  Do RAWDATA.Write("RawData")
  Set sc = ##class(dbo.spTIETest)."spTIETest"(OBJECT,NAMESPACE,CACHEVERSION,.RAWDATA)

Thanks,

Graham