The fortcomp_v10.zip file you have requested: Maps Levels Missions / Single Player / E to F Titles / Fortcomp (1.0) - 2.45mb is not available. Perhaps try browsing all files for the game Doom III and upload any files you want to share or are missing. This is the only information we could locate:
Instructions:Put the zip in your Doom3/base folder then extract the archive using the directory structure of the zip (or you could manually put the fortcomp named files in the base/maps folder and the other files, the sound ones, in base/sound). Th This sample level from Last Man Standing team is a great opening to the purpose of their mod: figthing hordes of enemies at a wild pace across multiple levels.