You refer to sound counter not found? That is a sound from A2 that is used in Wasteland, and does not exist in A3. Server admins can easily fix that by editing the mission and either remove class Counter in CfgSounds(usually in description.ext) OR grabbing the sound file from A2(or another sound to replace it) and edit the class accordingly. To remove the sound you also need to remove the code where it plays it, just search the mission for "counter".