There seems to be a copy and paste bug in the Solaris version of the CPU monitoring part of the agent.
The Agent refuses to monitor iowait on Solaris with ZBX_NOTSUPPORTED.

This should work up to Solaris 9, since Solaris 10 does not report iowaits anymore, but at least the agent does not refuse the test anymore, if you have template for several Solaris releases.