I bumped into the same problem and wasted a few CDs before asking the same question.
The answer is that OpenSolaris can be installed from a CD only on an intel/amd based server. Then you can use that server to install on sparc. Since I did not have an intel server to spare I eventually gave up on opensolaris. Too bad that Sun does not support Sparc CPUs first. MM. -- This message posted from opensolaris.org
