[Android Apps and Games] bagl0312:
I looked at my logcat, below are the relevant lines (I guess).

I see that the check about su fails:

[ 12-20 06:24:10.973 9873:0x2691 D/Voodoo OTA RootKeeper Utils ]
/system/xbin/su is not set-user-ID

even if the permissions are ok, as far as I can see:

shell@android:/ # ls -l /system/xbin/su
-rwsr-sr-x root root 22364 2011-12-20 06:36 su

I attach also a more complete logcat where I did several operations with the app

[ 12-20 06:23:54.340 476:0x1dc I/System.out ]
UPDATECOUNTERS REQUEST: org.projectvoodoo.otarootkeeper = 0

[ 12-20 06:23:54.340 476:0x1dc I/System.out ]
UPDATINGCOUNTERS: org.projectvoodoo.otarootkeeper = 0

[ 12-20 06:23:54.340 199:0xd2 I/ActivityManager ]
START {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 pkg=org.projectvoodoo.otarootkeeper cmp=org.projectvoodoo.otarootkeeper/.MainActivity} from pid 476

[ 12-20 06:23:54.488 199:0xd2 D/dalvikvm ]
GC_FOR_ALLOC freed 1261K, 11% free 26190K/29127K, paused 89ms

[ 12-20 06:23:54.488 199:0xe2 I/WindowManager ]
createSurface Window{4206ba90 Starting org.projectvoodoo.otarootkeeper paused=false}: DRAW NOW PENDING

[ 12-20 06:23:54.519 9873:0x2691 I/Voodoo OTA RootKeeper MainActivity ]
Starting app

[ 12-20 06:23:54.543 9873:0x2691 I/Voodoo OTA RootKeeper Device ]
/system mount point: /dev/block/platform/omap/omap_hsmmc.0/by-name/system /system ext4 ro,relatime,barrier=1,data=ordered 0 0

[ 12-20 06:23:54.543 9873:0x2691 I/Voodoo OTA RootKeeper Device ]
/system filesystem support extended attributes

[ 12-20 06:23:54.551 9873:0x2691 D/Voodoo OTA RootKeeper Utils ]
/system/xbin/su is not set-user-ID

[ 12-20 06:23:54.551 9873:0x2691 D/Voodoo OTA RootKeeper Device ]
Superuser.apk installed

[ 12-20 06:23:54.566 9873:0x2691 D/Voodoo OTA RootKeeper Device ]
attributes:

[ 12-20 06:23:54.598 9873:0x2691 D/Voodoo OTA RootKeeper Utils ]
Run script content (with shell: su):
#!/system/bin/sh
echo SuPermsOkay

[ 12-20 06:23:54.598 476:0x1dc D/OpenGLRenderer ]
Flushing caches (mode 1)

[ 12-20 06:23:54.598 199:0x188 W/InputManagerService ]
Starting input on non-focused client com.android.internal.view.IInputMethodClient$Stub$Proxy@41bf44c0 (uid=10218 pid=476)

[ 12-20 06:23:54.637 476:0x1dc D/OpenGLRenderer ]
Flushing caches (mode 0)

[ 12-20 06:23:54.652 9963:0x26eb E/su ]
sudb - Opening database

[ 12-20 06:23:54.652 9963:0x26eb E/su ]
sudb - Database opened

[ 12-20 06:23:54.652 9963:0x26eb E/su ]
sudb - Database closed

[ 12-20 06:23:54.652 9963:0x26eb D/su ]
10220 org.projectvoodoo.otarootkeeper executing 0 /data/data/org.projectvoodoo.otarootkeeper/files/commands.sh using shell /system/bin/sh : sh

[ 12-20 06:23:54.668 9873:0x2691 D/Voodoo OTA RootKeeper Utils ]
Superuser command auth confirmed

[ 12-20 06:23:54.699 199:0x1c37 I/WindowManager ]
createSurface Window{420ee6a0 Toast paused=false}: DRAW NOW PENDING

[ 12-20 06:23:54.715 9873:0x2692 D/dalvikvm ]
GC_CONCURRENT freed 374K, 4% free 14588K/15047K, paused 2ms+3ms

[ 12-20 06:23:54.730 9893:0x26a7 D/dalvikvm ]
GC_CONCURRENT freed 304K, 3% free 14220K/14599K, paused 2ms+2ms

[ 12-20 06:23:54.746 199:0x2200 I/WindowManager ]
createSurface Window{42091d98 org.projectvoodoo.otarootkeeper/org.projectvoodoo.otarootkeeper.MainActivity paused=false}: DRAW NOW PENDING

[ 12-20 06:23:54.894 199:0xd2 W/InputManagerService ]
Starting input on non-focused client com.android.internal.view.IInputMethodClient$Stub$Proxy@41bf44c0 (uid=10218 pid=476)

[ 12-20 06:23:55.105 199:0xe2 I/ActivityManager ]
Displayed org.projectvoodoo.otarootkeeper/.MainActivity: +599ms

[ 12-20 06:23:59.535 9873:0x2691 D/Voodoo OTA RootKeeper MainActivity ]
Button pressed tag: protect

[ 12-20 06:23:59.535 9873:0x2691 I/Voodoo OTA RootKeeper ProtectedSuOperation ]
Backup to protected su

[ 12-20 06:23:59.566 9873:0x2691 D/Voodoo OTA RootKeeper Utils ]
/system/bin/su is not set-user-ID

[ 12-20 06:23:59.566 9873:0x2691 D/Voodoo OTA RootKeeper Utils ]
Run script content (with shell: su):
mount -o remount,rw /system /system
/data/data/org.projectvoodoo.otarootkeeper/files/chattr -i /system/su-backup
cat /system/xbin/su > /system/su-backup
chmod 06755 /system/su-backup
/data/data/org.projectvoodoo.otarootkeeper/files/chattr +i /system/su-backup
mount -o remount,ro /system /system

[ 12-20 06:23:59.660 9969:0x26f1 E/su ]
sudb - Opening database

[ 12-20 06:23:59.660 9969:0x26f1 E/su ]
sudb - Database opened

[ 12-20 06:23:59.668 9969:0x26f1 E/su ]
sudb - Database closed

[ 12-20 06:23:59.668 9969:0x26f1 D/su ]
10220 org.projectvoodoo.otarootkeeper executing 0 /data/data/org.projectvoodoo.otarootkeeper/files/commands.sh using shell /system/bin/sh : sh

[ 12-20 06:23:59.699 199:0x1e7 I/WindowManager ]
createSurface Window{421dabb0 Toast paused=false}: DRAW NOW PENDING

[ 12-20 06:24:00.113 3092:0xc16 D/dalvikvm ]
GC_CONCURRENT freed 672K, 6% free 14581K/15495K, paused 4ms+3ms