The l4d_sv_forestfort.rar file you have requested: Maps Levels Missions / Survival Maps / Forest Fort - 2.07mb is not available. Perhaps try browsing all files for the game Left 4 Dead and upload any files you want to share or are missing. This is the only information we could locate:
A map I made to test out the new SDK. Press the white button on the barrel near the weapons, to start the survival event.