The NPE-G1 is supported in 12.2(4)BW, 12.2(15)B, 12.2(14)S, 12.2(14)SU, 12.2(15)T, 12.1(14)E, 12.3(1), 12.3(2)T, 12.0(28)S, 12.3(1a)B, and later Cisco IOS releases.
For the most current release information, refer
http://tools.cisco.com/Support/Fusion/FusionHome.do
HTH,
-amit singh