Non initialized Cmd Parameter Collection via ASP vs SQL Server 200

Hi!

I have some ancient VBScript code running in ASP 3.0. In our development 
area the code runs well, but at our customers server it fails claiming
that 
the parameter collection is not initialized. (IE. index out of range)
The stuff has run fine on SQL Server 2000 before, but the customer has 
upgraded to SQL Server 2005.
They haven't upgraded to SP 1 or 2 yet, but I'm not entirely sure that is 
the reason.

Any other possible reasons why the following code won't pre-populate the 
parameters collection with return value and one input parameter?
(I use storedproc = 4, "myProcedureName", "myConnection", Array(string) as

parameters here)
Of course it fails on Set oRetPm = oCmd.Parameters(0) since I have handled

the following statements. And the procedure has both return and parameter.
;)

function runCommand(nCommandType, sCommandText, vConn, aParameters, byref 
vRetVal)
dim oCmd
dim oRetPm
dim i

	runCommand = false

	Set oCmd = Server.CreateObject("ADODB.Command")
	if isObject(vConn) then
		Set oCmd.ActiveConnection = vConn
	else
		oCmd.ActiveConnection = vConn
	end if
	
	oCmd.CommandType = nCommandType
	oCmd.CommandText = sCommandText
	
	Set oRetPm = oCmd.Parameters(0)
	if isArrayInited(aParameters) then
		for i = 0 to ubound(aParameters)
			Response.Write "<!-- " & oCmd.Parameters(i + 1).Name & " : " & 
aParameters(i) & " -->" & vbCrLf
			on error resume next
			oCmd.Parameters(i + 1).Value = aParameters(i)
			if Err.number <> 0 then
				Response.Write "<!-- " & Err.description & " -->"
				Set oCmd = nothing
				runCommand = false
				exit function
			end if
			on error goto 0
		next
	end if

-- 
Lars-Erik