ok so im guessing you have added extra sounds in your map ? well this is a way of fixing this ,not saying its the best but it will work
ok go to root /raw/soundaliases then find the file called weapons.csv copy that file and paste it in the same location but remname it to weapons_backup.csv ,(tbh i would put a copy of the weapons_backup.csv in another folder on your pc for safe keeping incase you fuck up in the future
ok so you have two files in that location
weapon.csv and weapons_backup.csv good ( 100% make sure you make the back up file ok )
open up weapons.csv with note pad and look for any guns sound you dont have in your map
example : if you dont have the Arisaka Sniper in your map delete the code below
#Arisaka Sniper,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
weap_arisaka_fire_plr_snp,,SFX/Weapon/Rifle/Arisaka_snp/Fire/wpn_arisaka_snp_st_f.wav,,1,1,,,,,,,rfl_1st,,curve3,,,,,0.98,1.04,,2d,,,,0.75,pel1b mak test oki2 oki3 pel1 pel1a mak audio_test_tuey firing_range pel2 living_battlefield all_mp,,,weap_arisaka_act_snp_plr,,,wpn_all,,,,,,,,,,,,90,90,0.25,1,,
weap_arisaka_act_snp_plr,,SFX/Weapon/Rifle/Arisaka_snp/Fire/wpn_arisaka_snp_st_act.wav,,1,1,,,,,,,rfl_1st,,curve3,,,,,1,1,,2d,,,,,pel1b mak test oki2 oki3 pel1 pel1a mak audio_test_tuey firing_range pel2 living_battlefield all_mp,,,weap_arisaka_snp_move_l,,,wpn_all,0.25,0.5,,,,,,,,,,90,90,0.25,1,,
weap_arisaka_fire_snp,,SFX/Weapon/Rifle/Kar_98/fire/mono_##,,0.8,0.9,1000,5000,10,priority,2,oldest,rfl_3rd,,curve4,,,,,0.95,1.05,pitch,3d,,,,0.7,pel1b mak_test oki2 oki3 pel1 pel1a mak audio_test_tuey firing_range pel2 living_battlefield all_mp,,,weap_arisaka_fire_dist_snp,,,,,,,,,0.2,,,,,,50,90,0.35,1,,
weap_arisaka_fire_dist_snp,,SFX/Weapon/dist/jap/dist_jap_rifle.wav,,0.8,0.9,1000,10000,10,priority,2,oldest,dist_wpn,,curve2,0.8,12000,rcurve1,rcurve3,0.85,1.05,pitch,3d,,,,0.7,pel1b mak test oki2 oki3 pel1 pel1a mak audio_test_tuey firing_range pel2 living_battlefield all_mp,,,weap_arisaka_snp_move_l,,,,,,,,,,,,no,,,70,20,0.35,1,,
weap_arisaka_snp_ring_mn,,SFX/Weapon/Rifle/snpr_ring/snpr_mauser_##,,0.8,0.9,1000,10000,10,priority,2,oldest,rfl_3rd,,curve4,,,,,0.95,1.05,pitch,3d,,,,0.7,pel1b mak_test oki2 oki3 pel1 pel1a mak audio_test_tuey firing_range pel2 living_battlefield all_mp,,,weap_arisaka_fire_dist,,,,,,,,,0.2,,,,,,50,90,0.35,1,,
gr_arisaka_shell_in_plr,,SFX/Weapon/Rifle/Kar_98/Foley/round_in_##,,0.75,0.8,,,,,,,reload,,,,,,curve4,0.95,1.05,,2d,,,,,pel1b mak_test oki2 oki3 pel1 pel1a mak audio_test_tuey firing_range pel2 living_battlefield all_mp,,,,,,,,0.5,,,,,,,,,,80,95,0.55,1,,
now recompile your map and see if it runs as you have just deleted 6 sounds
this should work if you still get the error try deleting another gun until the game starts
once you have finished your map and have released it you can go back into root/raw/soundaliases and find the two files made before weapons.csv and weapons_backup.csv
delete the weapons.csv THEN rename the weapons_backup.csv to just weapons.csv so when you make your next map you have all the sounds for all the guns still
hope this fixes your problem