THX!!! 
 
I have the same problem, Redhat must solve the problem by RHN Updates. 
 
Good Luck!. 

Think I found the problem:

If I have an entry "Language=C" in ~/.kde/share/config/kdeglobals,
then the desktop files under /etc/X11/applnk will not show
up in the menues. If I remove the "C", they will show up.

 yes, and this bashline can also solve the problem :)  
  
ls -1 /etc/X11/applnk/ | awk '{print "cp -a /etc/X11/applnk/"$1"  
/usr/share/applnk/"}' | bash  
  
this copy applnk directories to applnk, but better is solve the problem with   
 remove "C" from this file, because if I install new program, this program 
will copy itself to /etc/X11/applnk/ and no to /etc/X11/applnk/ and I'll to 
excecute my line already. 
 

I upgrade from 7.2 to 7.3.  I have the same problem.  Additionally, when I went
into Gnome the items were there, but they were below the other items in the same
menu, not in  the usual order.  I looked at Gnome menu editor, and these entries
were listed in the "to be merged" section.  (I don't use Gnome much, so I'm not
sure what this means.)

Here's another variation for a solution (for KDE anyway):
KDE>Control Center>Country & Language>Add Language>"English US"

This makes the line in ~/.kde/share/config/kdeglobals say

Language=en_US:C

I restarted KDE and my menus returned. 

I also did not see all my menu items after a 7.2 to 7.3 upgrade.
I went to control center and added US English and all the items I could see in
the menu editor now show up in the K menu.
There should be an "up2date" fix for this because customizing menus is very
important!

Same problem here, except adding US English does NOT solve the problem.

Can not use Enaglish US.. in cz environment. Still using it does not help.

It looks like if the default language is not en_US it does not
work. At least the entries are gone for every user who uses
german as main language here. Moreover, the entries are entirely
ignored by kde. In particular, all apps are not available to
the file manager as well. This is a serious problem here and
should be fixed ASAP!

Same problem here. Together with the dcopserver bug (#65460) this calls 
for an immediate kdebase (and maybe also kdelibs) update! I don't know 
how many more bugs are there lurking in the KDE packages which could 
have been found by QA easily.

Had language 'C' after an upgrade from 7.2 to 7.3 and needed to change the
language to "English US" to get back many menu entries in "System"
(/etc/X11/applnk).

KMenu > Preferences > Personalization > Country & Language

I've noticed not all menu entries are translated to many languages. I'm unable
to get those menu entries for KDE language "German" and a "de_DE@euro" locale.

Some menue entries are not visible but in the menu editor they are visible. If I edit them (does not matter what I edit, but I need to edit something to 
enable the "apply" button) and klick on apply they appear in the menu. I use Redhat 7.3, KDE 3.0.0 with german language.

this problem doesn't appear with kdebase-3.0.0-2 (also not with kdebase in 2nd
skipjack, dont have it here to tell release number)

The entries are missing in polish locale too.
If they are edited, the new version is stored in the user directory
(~/.kde/share/applnk) and so becomes visible.

this bug is actually in kdelibs not kdebase.

proof:
after upgrading kdelibs w/o kdebase from 3.0.0-4 to 3.0.0-12 (valhalla) the menu
entries disappeared

please change bug accordingly

*** Bug 68024 has been marked as a duplicate of this bug. ***

it's fixed in Fedora Core1 release.