Terrain Generation help!!!

[stevahnyo]

A few years ago, with the help of "Shadowrend" I created a game called "Thin Miner" lost the files, and found it years later. I have been having EXTREME difficulty trying to fix a simple generation where there are random spaces in the terrain. id like to remove that and keep the terrain full. Any help would be appreciated!!!! Heres the photo of how the terrain looks and the codes for it. If you need anymore let me know!
Also, here's "Terrain_data" since I can only post 5 photos..


function terrain_data(){
rw=room_width;
rh=room_height;
ml=argument0;
tl=argument1; //Top Limit
bh=16;
bw=16;
max_offset=argument2;
max_jump=argument3;

LIST_TERRAIN_X=ds_list_create();
LIST_TERRAIN_Y=ds_list_create();

cur_x=0;
cur_y=0;

h=0;
w=0;

ch=floor((tl+choose(random(max_offset),-random(max_offset)))/bh);
}