Invoke Problem

#include "SDK\amx\amx.h"
#include "SDK\plugincommon.h"
#include "SDK\Invoke.h"

typedef void (*logprintf_t)(char* format, ...);

logprintf_t logprintf;
extern void *pAMXFunctions;

using namespace std;

int P_GiveWeapon ( int playerid, int gunid, int ammo );

cell AMX_NATIVE_CALL P_GiveWeapon(AMX* amx, cell* params)
{
    g_Invoke->callNative(&PAWN::GivePlayerWeapon, params[1], params[2], params[3]);
    return 1;
}

PLUGIN_EXPORT unsigned int PLUGIN_CALL Supports()
{
    return SUPPORTS_VERSION | SUPPORTS_AMX_NATIVES;
}

PLUGIN_EXPORT bool PLUGIN_CALL Load(void **ppData)
{
    g_Invoke = new Invoke;

    pAMXFunctions = ppData[PLUGIN_DATA_AMX_EXPORTS];
    logprintf = (logprintf_t) ppData[PLUGIN_DATA_LOGPRINTF];

    logprintf(" * Test plugin was loaded.");
    return true;
}

PLUGIN_EXPORT void PLUGIN_CALL Unload()
{
    logprintf(" * Test plugin was unloaded.");
}

AMX_NATIVE_INFO PluginNatives[] =
{
    {"P_GiveWeapon", P_GiveWeapon},
    {0, 0}
};

PLUGIN_EXPORT int PLUGIN_CALL AmxLoad( AMX *amx )
{
    g_Invoke->amx_list.push_back(amx);
    return amx_Register(amx, PluginNatives, -1);
}

PLUGIN_EXPORT int PLUGIN_CALL AmxUnload( AMX *amx )
{
    for(list<AMX *>::iterator i = g_Invoke->amx_list.begin(); i != g_Invoke->amx_list.end(); ++i)
    {
        if(*i == amx)
        {
            g_Invoke->amx_list.erase(i);
            break;
        }
    }
    return AMX_ERR_NONE;
}