rd9488 I finally figured it out. Not sure if you already did but this is what I did to solve that error message.
add new string
set bot_mp_special_grenade ""
Insert "" with ONE of these official asset strings:
willy_pete_mp (Smoke Grenade / White Phosphorus)
tabun_gas_mp (Tabun Gas)
signal_flare_mp (Signal Flare)
concussion_grenade_mp (Concussion Grenade)
Examples: set bot_mp_special_grenade "willy_pete_mp"
set bot_mp_special_grenade "tabun_gas_mp"
set bot_mp_special_grenade "signal_flare_mp"
set bot_mp_special_grenade "concussion_grenade_mp"
