I had a problem with AS400 ODBC drivers for some years ago. Qlikview wasn't included that time, just importing data via ODBC.
To be able to import all the records I needed to increase the timeout value in the odbc-driver settings.
But that odbc-driver could have been another then the one you're using. I can check what manufacturer we bought that one from when I come in to the office in about 8-9 hours.