Chester is correct, you're running an outdated version.

If you can't find it in the maps folder, try going to your Garry's Mod root folder where materials, sound, addons etc. are and search drp_ext in the search bar. Delete any .bsp files that come up.

Also, ensure that you aren't subscribed to any addon for the downtown_v4c_v2_drp_ext version other than this one:

steamcommunity.com/sharedfiles/filedetails/?id=210544459

Topic locked.

Chester is correct, you're running an outdated version. If you can't find it in the maps folder, try going to your Garry's Mod root folder where materials, sound, addons etc. are and search drp_ext in the search bar. Delete any .bsp files that come up. Also, ensure that you aren't subscribed to any addon for the downtown_v4c_v2_drp_ext version other than this one: http://steamcommunity.com/sharedfiles/filedetails/?id=210544459 Topic locked.