unexpected free inode

unexpected free inode 208925, run fsck(1M)
this is happening on a Solaris 8 system.
It means that something deleted a file on the disk without going
through the filesystem driver to do it.
Some sort of raw access to the /dev/rdsk device file or some bug.
The filesystem must be umounted and fsck must be run on it. If
there is further filesystem corruption at some point it can
trigger a panic.
In the meantime, do all of the usual checks to be sure the device
is not being accessed raw. Not a swap device, not a database
devices, and so on. And audit the rest of the messages file to
see if there are any hints about hardware problems.