Strange, GoTR didn't break my multiplayer games. Must be some other mod doing it. One way I know to fix this type of problem is to make sure you and your friends have the exact same mods installed in the their games. Always after building the GoTR patch on your end make sure your friends have the same files ( patch.vpp_pc, preload.tbl, and the preload_anim.tbl files) as you have before taking them out of the "MY_CUSTOM_PATCH" folder. If they haven't done so you can send them a copy of your ( patch.vpp_pc, preload.tbl, and the preload_anim.tbl ) files that way everything will be compatible.