Actually, I believe the drivers that are available on the NI website are licened for upgrades only. If the hardware came with an NI-488.2 driver, you can upgrade that to the latest version with the link above.
If your purchase did not include a software license (the hardware is sold separately from the hardware due to single- and multi-user license options), you need to purchase a license of NI-488.2.
http://sine.ni.com/apps/we/nioc.vp?cid=10622〈=US
The part numbers for the single and multi-user license for Windows are 778598-02 and 778598-01. Other operating systems are listed as well.
If you have any confusion, you should contact NI to confirm licensing issues.