I created a ufsdump of a directory (opt) to a file. The partition it was on had to be resized. I resized the partition. I did a newfs on it. I remounted the partition. I ran ufsrestore fs /tmp/opt.dmp in the /opt directory. It worked the first time. Then I found out I had to resize the partition. I resized and did a newfs on the partition and mounted it. This time I get the following error several times (inode ####(inode number)) not found on volume.
What is the cause of ufsrestore not working?
It's called a bug. 
Make a list of those inode numbers. Then do a "restore -tv" to get a list of all of the file together with the inode numbers. Look at the list to see what files it was complaining about. Look on your disk to see if those files are really missing. If so extract them.
I ran ufsrestore -tvf. It had:
Label: none
dir 2 .
dir 656 ./dev
dir 7567 ./dev/rmt
leaf 7735 ./dev/rmt/c1t0d0s6
I tried to extract. Nothing worked. It created a directory under /opt which was /opt/dev/rmt/ with c1t0d0s6 in the directory, which says it is a ufsdump archive file. I tried to extract that file, but no luck.
There should be no such thing as /dev/rmt/c1t0d0s6. You needed to use something like /dev/rdsk/c1t0d0s6 the last parameter as when you ran ufsdump.
Hi
try running in interactive mode and see if it shows you the contents of the dump.
I think you can try to increase the inodes number in this file system maybe its help.