check your amxx.cfg to see if your debug settings are set right. I have very little experience with weapons and ammo, so I am not going to waste your time guessing what is right.
// Plugin Debug mode
// 0 - No debugging (garbage line numbers)
// 1 - Plugins with "debug" option in plugins.ini are put into debug mode
// 2 - All plugins are put in debug mode
// Note - debug mode will affect JIT performance
amx_debug 1