kmenu-gnome-0.6-3.fc5.noarch.rpm
  File conflict with: /usr/share/desktop-directories/kde-games-kids.directory
  => Package conflicts with: kdebase - 6:3.5.4-0.5.fc5.i386

I'll have a look.

However can you describe to me how you got this issue ?

I've tried it on my rawhide ("yum install kmenu-gnome", but didn't get any
conflicts.

With an automated file-conflicts checker. But it is reproducible with yum:

$ sudo yum install kdebase kmenu-gnome
Loading "installonlyn" plugin
Setting up Install Process
Setting up repositories
Reading repository metadata in from local files
Parsing package install arguments
Resolving Dependencies
--> Populating transaction set with selected packages. Please wait.
---> Package kmenu-gnome.noarch 0:0.6-4.fc6 set to be updated
---> Package kdebase.i386 6:3.5.4-9.fc6 set to be updated
--> Running transaction check
--> Processing Dependency: libsensors.so.3 for package: kdebase
--> Processing Dependency: htdig for package: kdebase
--> Restarting Dependency Resolution with new changes.
--> Populating transaction set with selected packages. Please wait.
---> Package htdig.i386 3:3.2.0b6-6.4.3 set to be updated
---> Package lm_sensors.i386 0:2.10.0-3.1 set to be updated
--> Running transaction check

Dependencies Resolved

=============================================================================
 Package                 Arch       Version          Repository        Size 
=============================================================================
Installing:
 kdebase                 i386       6:3.5.4-9.fc6    development        29 M
 kmenu-gnome             noarch     0.6-4.fc6        extras-development  271 k
Installing for dependencies:
 htdig                   i386       3:3.2.0b6-6.4.3  development       1.0 M
 lm_sensors              i386       2.10.0-3.1       development       494 k

Transaction Summary
=============================================================================
Install      4 Package(s)         
Update       0 Package(s)         
Remove       0 Package(s)         

Total download size: 30 M
Is this ok [y/N]: Downloading Packages:
Running Transaction Test
Finished Transaction Test


Transaction Check Error:   file
/usr/share/desktop-directories/kde-games-kids.directory conflicts between
attempted installs of kdebase-3.5.4-9.fc6 and kmenu-gnome-0.6-4.fc6