iwlist error

[Aaron Konstam]

When I run iwlist I get the following error:
[root at localhost network-scripts]# iwlist eth1 retry
Warning: Driver for device eth1 has been compiled with version 20
of Wireless Extension, while this program supports up to version 19.
Some things may be broken...

The same error is generated by iwconfig. How can it be fixed?
-- 
Aaron Konstam <akonstam at sbcglobal.net>