Forum member npierce has fixed it:
I applied the patch manually, as the latest /usr/sbin/filmnt has internationalization changes.
Here is the Woof commit:
Comments:Posted on 21 Feb 2012, 17:48 by BarryK
Correction, it is not really a "corner case". If we have many frugal installs of Puppy, we may have many *save.2fs or *save.3fs files of same name.