Backup Exec 2014 Agents on Exchange 2013

We are running Backup Exec 2014 and have a new Exchange 2013 server running in VMWare, to replace our 2007 server. we can migrate mailboxes ok, but when I install the Backup Exec agents on the Exchange 2013 Servers (2), The migration stops working, The agents seem to block RPC from working between the new and the old Exchange servers. Has anybody heard of this before?

Thanks

Pat