If you don't know how to instal a .umod file you need to read this! :)
just simply doubleclick on the .umod file and they ask for your unrealtournament folder
just fill in the location of your unrealtournament folder there. like mines for example:
D:\UnrealTournament ;)
If you can't install the .umod file you can download the loose files here:
http://members.lycos.nl/y0ni/UTMAPS/Flagsy0ni.zip

Put the .utx file in your textures folder.
Put the .u file in your system folder.

y0ni

Credits to WaZaaa who made the .u file for me ;)