A couple of questions:
1) Is the FLEXlm licensing software set up properly on the server? For more information, go to this web page and follow the Vendor Daemons link.
2) The licensing software comunicates on certain TCP ports in order to function. This requires that these ports be open (unblocked). Your network administrator needs to ensure that the firewall is not blocking these ports.
3) Even though your network adminstrator says the ports are unblocked, insist that he do it. Nine out of ten floating-license problems, from my experience, are because to these critical ports being blocked, even though the IT person says that they aren't. The licensing software can generate a log that can help you spot problems with the network.
---Tom