While my personal experience with Sun Solaris is somewhat limited, what I'm about to say pretty much fits into any type of installation....
If your planning to install an operating system, then make sure you have enough space for the essential files! In your case, you mentioned a clean install and the root partition has already reached 100% of use.
I strongly recommend you consider reinstalling the O/S but this time being more generous to the amount of space you will assign to the root '/' partition :wink:
I can get you some awesome information regarding this and I will as soon as I get back to work. I will need an email address to send it to tho. The basic gist of it is that patches by default install into the /var/sadm/ directory. Essentially what we will have you do is put a filesystem on another slice cpio everything from /var/sadm/ onto this and then mount that new /var/sadm/ directory by creating a mount point. all in all you will save alot of space on root.