take also care about this info:
Solaris Cluster 4.x System Panic During Solaris Cluster Update to 4.1 SRU 1 to SRU 5 (Doc ID 1637438.1)
Solaris Cluster need its own license. If you already have a 4.0 license then you are fine. If not, you need an additional Solaris Cluster license.
Please see page6 - Licensing of