Segmentation Fault

[noey699]

#include <allegro.h>

BITMAP *RedBlock;
BITMAP *BlueBlock;
BITMAP *WhiteBlock;
BITMAP *GreenBlock;
BITMAP *BlackBlock;
BITMAP *Background;
BITMAP *Background2;
BITMAP *buffer;
//BlockColor 0 = no block 1 = redblock 2 = blueblock 3 = whiteblock 4 = greenblock
int BlockColor[15][17] = {{0},{0}};
int color;
int BlockPosX [15];
int BlockPosY [17];
int CounterPos = 0;
void NewGame(){

}
int MoveSingleBlock( int Blockx, int Blocky, int color1 ){
    if ( color1 == 1 ){
        draw_sprite( Background2, BlackBlock, BlockPosX[Blockx], BlockPosY[Blocky] );
        draw_sprite( Background2, RedBlock, BlockPosX[Blockx], BlockPosY[Blocky - 1]);
    }
    if ( color1 == 2 ){
        draw_sprite( Background2, BlackBlock, BlockPosX[Blockx], BlockPosY[Blocky] );
        draw_sprite( Background2, BlueBlock, BlockPosX[Blockx], BlockPosY[Blocky - 1]);
    }
    if ( color1 == 3 ){
        draw_sprite( Background2, BlackBlock, BlockPosX[Blockx], BlockPosY[Blocky] );
        draw_sprite( Background2, WhiteBlock, BlockPosX[Blockx], BlockPosY[Blocky - 1]);
    }
    if ( color1 == 4 ){
        draw_sprite( Background2, BlackBlock, BlockPosX[Blockx], BlockPosY[Blocky] );
        draw_sprite( Background2, GreenBlock, BlockPosX[Blockx], BlockPosY[Blocky - 1]);
    }
}
void MoveBlocks(){
    int x = 17;
    int i = 0;
    while ( x != 0 ){
        while( i != 15 ){
            if (BlockColor[i][x - 1] == 0 ){
                MoveSingleBlock(BlockPosX[i], BlockPosY[x], BlockColor[i][x]);
            }
            i = i + 1;
        }
        x = x - 1;
}
}
void SetBlockPos(){
   BlockPosX[0] = 122;
   BlockPosX[1] = 148;
   BlockPosX[2] = 174;
   BlockPosX[3] = 200;
   BlockPosX[4] = 226;
   BlockPosX[5] = 252;
   BlockPosX[6] = 278;
   BlockPosX[7] = 304;
   BlockPosX[8] = 330;
   BlockPosX[9] = 356;
   BlockPosX[10] = 382;
   BlockPosX[11] = 408;
   BlockPosX[12] = 434;
   BlockPosX[13] = 460;
   BlockPosX[14] = 486;

   BlockPosY[0] = 455;
   BlockPosY[1] = 429;
   BlockPosY[2] = 403;
   BlockPosY[3] = 377;
   BlockPosY[4] = 351;
   BlockPosY[5] = 325;
   BlockPosY[6] = 299;
   BlockPosY[7] = 273;
   BlockPosY[8] = 247;
   BlockPosY[9] = 221;
   BlockPosY[10] = 195;
   BlockPosY[11] = 169;
   BlockPosY[12] = 143;
   BlockPosY[13] = 117;
   BlockPosY[14] = 91;
   BlockPosY[15] = 65;
   BlockPosY[16] = 39;


}
void newline(){

    int i = 0;
    while (i != 15){
        color = rand()&#37;4;
    if (color == 0){

        draw_sprite(Background2, RedBlock, BlockPosX[i], BlockPosY[16]);
        BlockColor[i][17] = 1;
        i = i + 1;

    }
    if (color == 1){

        draw_sprite(Background2, BlueBlock, BlockPosX[i], BlockPosY[16]);
        BlockColor[i][17] = 2;   //i believe this is line 103
        i = i + 1;

    }
    if (color == 2){

        draw_sprite(Background2, WhiteBlock, BlockPosX[i], BlockPosY[16]);
        BlockColor[i][17] = 3;     
        i = i + 1;

    }
    if (color == 3){

        draw_sprite(Background2, GreenBlock, BlockPosX[i], BlockPosY[16]);
        BlockColor[i][17] = 4;
        i = i + 1;

    }
}
}



int main(){
    //initialize allegro
    allegro_init();
    install_timer();
    install_keyboard();
    install_mouse();
    srand(time(NULL));
    set_color_depth(16);
    set_gfx_mode( GFX_AUTODETECT, 640, 480, 0, 0);
    //set the block positions
    SetBlockPos();
    //load needed bitmaps
    buffer = create_bitmap( SCREEN_W, SCREEN_H );
    Background2 = create_bitmap( SCREEN_W, SCREEN_H );
    Background = load_bitmap( "background.bmp", NULL);
    RedBlock = load_bitmap( "redblock.bmp", NULL);
    WhiteBlock = load_bitmap( "whiteblock.bmp", NULL);
    BlueBlock = load_bitmap( "blueblock.bmp", NULL);
    GreenBlock = load_bitmap( "greenblock.bmp", NULL);
    BlackBlock = load_bitmap( "blackblock.bmp", NULL);
    //newline and MoveBlocks timer
    install_int_ex(newline, SECS_TO_TIMER(5));
    install_int_ex(MoveBlocks, MSEC_TO_TIMER(50));
    //make a background i can draw on
    draw_sprite(Background2, Background, 0, 0);
    //main game loop
    while ( !key[KEY_ESC] ){
    //acquire screen for writing
    acquire_screen();
    //draw the background to buffer

    draw_sprite(buffer, Background2, 0, 0);

    //release screen
    release_screen();
    blit(buffer, screen, 0, 0, 0, 0, SCREEN_W, SCREEN_H);
    rest(80);
    }

    return 0;

}
END_OF_MAIN();

I cannot figure out where this error is coming from. This is my first full game, so forgive me if it is sloppy at all but I would really appreciate it if you could help me with this problem ASAP. I am using Allegro which already declares all the include files needed for C++. The error always points at line 103, I have the line marked with a comment. Thank you in advanced.

also my operating system is vista