[Exolent ID]

A little plain one is additional. If to a wall or land you beat the knife then will scintillate.

[kramesa]

You are not allowed to post .amxx files.

[tuty]

just a tip

#include < amxmodx >
#include < fakemeta >
#include < hamsandwich >

#pragma semicolon 1

#define PLUGIN_VERSION  "1.0.0"

new gKnifeHitDecalIndex[ 2 ];

new gMaxClients;

public plugin_init()
{
    register_plugin( "Knife Hit Decal", PLUGIN_VERSION, "tuty" );

    RegisterHam( Ham_TraceAttack, "worldspawn", "bacon_TraceAttackWorldspawn" );
    
    gMaxClients = get_maxplayers();
}

public plugin_precache()
{
    gKnifeHitDecalIndex[ 0 ] = engfunc( EngFunc_DecalIndex, "{crack1" );
    gKnifeHitDecalIndex[ 1 ] = engfunc( EngFunc_DecalIndex, "{crack2" );
}

public bacon_TraceAttackWorldspawn( iVictim, iAttacker, Float:flDamage, Float:flDirection[ 3 ], iTr, iDamageBits )
{
    if( 1 <= iAttacker <= gMaxClients )
    {
        if( get_user_weapon( iAttacker ) == CSW_KNIFE )
        {
            new Float:flEndOrigin[ 3 ];
            get_tr2( iTr, TR_vecEndPos, flEndOrigin );
            
            UTIL_WorldDecal( flEndOrigin, gKnifeHitDecalIndex[ random_num( 0, charsmax( gKnifeHitDecalIndex ) ) ] );
        }
    }
}

stock UTIL_WorldDecal( Float:flOrigin[ 3 ], iDecal )
{
    engfunc( EngFunc_MessageBegin, MSG_PAS, SVC_TEMPENTITY, flOrigin, 0 );
    write_byte( TE_WORLDDECAL );
    engfunc( EngFunc_WriteCoord, flOrigin[ 0 ] );
    engfunc( EngFunc_WriteCoord, flOrigin[ 1 ] );
    engfunc( EngFunc_WriteCoord, flOrigin[ 2 ] );
    write_byte( iDecal );
    message_end();
}

this will be better than your code you can use it

[sami_spt]

The author is banned.. I dont think he can support it anymore.