PBO loses settings when power cycled

Starting from this week, I noticed that my Patriot Box Office (PBO) asked me to select language and time and network settings every time when it came out of the stand-by mode or power cycle. I tried downgrading the firmware back to P02 then flashed back to P70R2(BCN) but that didn't fix the problem.

I telnet to the BOX and found the file for the above settings is located at
/usr/local/etc/dvdplayer/Setup
and every time  when the PBO is turned on, this file is recreated upon user selections. I found the reason is most likely that the partition /usr/local/etc/ is full and the Setup file can't be saved to disk when powered off. Below is the result from df showing exactly that.
# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/root                78.6M     71.0M   7.6M  90% /
/dev/mtdblock/2          69.1M     69.1M      0 100% /usr/local/etc
/dev/rd/0                40.0k     40.0k      0 100% /mnt/rd

I deleted some RSS files I added and then did a du on the disk usage of partition /usr/local/etc

/usr/local/etc # du -d 1
54      ./playlist
874     ./dvdplayer
14      ./hdd.old
36660   ./linked
23827   ./mos
11      ./ppp
1962    ./srjg
2       ./lost+found
63419   .

The two biggest subfolders are linked (>30MB) and mos (>20MB). I found there are some redundant executables in

/usr/local/etc/linked/opt/bin
/usr/local/etc/mos/rssex

So I deleted those files and replace them with symbolic links to files in /usr/local/etc/mos/rssex2/bin/ After doing this, I now have roughly 7.5MB space in /usr/local/etc again.

 # df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/root                78.6M     71.0M      7.6M  90% /
/dev/mtdblock/2          69.1M     61.6M      7.5M  89% /usr/local/etc
/dev/rd/0                40.0k     40.0k         0 100% /mnt/rd

And PBO can save the Setup file correctly and no longer asks me to do initial setups.