ADO Connection with Postgres

Hello,

I am trying to connect to a postgres database in ASP (vbscript) and insert a blob into a bytea field. However I cannot
createan open connection via the following method. 

Any help/suggestions would be appreciated.

ConnectionString = "Driver={PostgreSQL};Server=<servername>;Port=5432;Database=imagedb;UID=imageUser"

Set rs = Server.CreateObject("ADODB.Recordset")
rs.Open "image_table", connectionString, adOpenKeyset, adLockOptimistic, adCmdTable
'After I run rs.open the following error eheck gives me the following error:
if err then
  response.write("<br><br>" & err.Description & " errorNum= " & Err.number)
end if
'Arguments are of the wrong type, are out of acceptable range, or are
'in conflict with one another. errorNum= 3001
'not sure what to change there
rs.begintrans
rs.AddNew
 rs("img_name") = nameRef 'name of the file
 rs("img").AppendChunk fileData 'file data being some binary data
rs.Update
rs.committrans
rs.Close
Set rs = Nothing

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