Here are all the errors when you compile this plugin if it helps:
//// l4d_multiple_equipment.sp
// l4d_multiple_equipment.sp(101) : warning 225: unreachable code
// l4d_multiple_equipment.sp(105) : warning 217: loose indentation
// l4d_multiple_equipment.sp(120) : warning 225: unreachable code
// l4d_multiple_equipment.sp(124) : warning 217: loose indentation
// l4d_multiple_equipment.sp(144) : warning 203: symbol is never used: "name"
// l4d_multiple_equipment.sp(59
: warning 204: symbol is assigned a value that
is never used: "set"
// l4d_multiple_equipment.sp(101
: warning 203: symbol is never used: "removea
ttach"
// l4d_multiple_equipment.sp(1064) : warning 203: symbol is never used: "CopyVec
tor"
// l4d_multiple_equipment.sp(9) : warning 203: symbol is never used: "Debug"
// l4d_multiple_equipment.sp(9 -- 1064) : warning 203: symbol is never used: "Dr
opPrimarayWeapon_l4d2"
// l4d_multiple_equipment.sp(1050) : warning 204: symbol is assigned a value tha
t is never used: "GameMode"
// l4d_multiple_equipment.sp(1050 -- 1064) : warning 203: symbol is never used:
"GetInfoFromName"
// l4d_multiple_equipment.sp(1050 -- 1064) : warning 203: symbol is never used:
"GetPrimaryWeaponCount"
// l4d_multiple_equipment.sp(1050 -- 1064) : warning 203: symbol is never used:
"IsSlot3"
// l4d_multiple_equipment.sp(1050 -- 1064) : warning 203: symbol is never used:
"IsSlot4"
// l4d_multiple_equipment.sp(1050 -- 1064) : warning 203: symbol is never used:
"IsSlot5"
// l4d_multiple_equipment.sp(1050 -- 1064) : warning 203: symbol is never used:
"IsValidEntRef"
// l4d_multiple_equipment.sp(1050 -- 1064) : warning 203: symbol is never used:
"IsValidEntRefS"
// l4d_multiple_equipment.sp(1050 -- 1064) : warning 203: symbol is never used:
"IsWeapon"
// l4d_multiple_equipment.sp(43) : warning 203: symbol is never used: "LastWeapo
n"
// l4d_multiple_equipment.sp(34) : warning 203: symbol is never used: "Slot3Name
"
// l4d_multiple_equipment.sp(35) : warning 203: symbol is never used: "Slot4Name
"
// l4d_multiple_equipment.sp(36) : warning 203: symbol is never used: "Slot5Name
"
// l4d_multiple_equipment.sp(50) : warning 203: symbol is never used: "g_gamesta
rt"
// l4d_multiple_equipment.sp(12) : warning 203: symbol is never used: "g_iVeloci
ty"
// l4d_multiple_equipment.sp(11) : warning 203: symbol is never used: "g_sprite"