This is easy to fix, just go to the bazooka_ammo.fpe and change the file.
The file has a extra command (isweapon = ww2bazooka) giving you bazooka just take it out since the ammo isn't a weapon that line is what is giving you the bazooka when you pick it up.
Just go to The Game CreatorsFPS CreatorFilesentitybankww2items folder and find the bazooka.fpe and delete that line and it will work fine.
here is the correct .fpe
;Entity Spec
;Header
desc = bazooka_ammo
;AI
aiinit = appear2.fpi
aimain = ammo.fpi
aidestroy = disappear2.fpi
;Spawn
spawnmax = 1
spawndelay = 500
spawnqty = 1
;Orientation
model = bazooka_ammo.X
offx = 0
offy = 0
offz = 0
rotx = 0
roty = 0
rotz = 0
scale = 100
fixnewy = 0
;Visualinfo
texturepath = gamecoregunsww2bazooka
textured = ammo_D2.tga
transparency = 1
isimmobile = 1
;Identity Details
isammo = 1
hasweapon = ww2bazooka
quantity = 3
;Decals
decalmax = 1
decal0 = glowzone
edited: oops i ready for bed and half asleep when i wrote this yesterday, i said change bazooka.fpe, i should have typed change bazooka_ammo.fpe by taking out the isweapon = ww2bazooka hopefully if anyone tried it they looked at the code box and knew what i was saying.