I've been trying to get this game to function, but for some reason, it just doesn't want to. I have no idea what the hell this error message is, but here's the entire thing.

ArgumentError:comparison of Integer with nil failed
-Ruby-files/Game/Game_Follower.rb:145:in '<='
-Ruby-files/Game/Game_Follower.rb:145:in 'update'
-Ruby-files/Scenes/Scene_Map.rb:175:in 'block (2 levels) in update'
-Ruby-files/Scenes/Scene_Map.rb:175:in 'each'
-Ruby-files/Scenes/Scene_Map.rb:175:in 'block in update'
-Ruby-files/Scenes/Scene_Map.rb:159:in 'loop'
-Ruby-files/Scenes/Scene_Map.rb:159:in 'update'
-Ruby-files/Scenes/Scene_Map.rb:86:in 'block in main'
-Ruby-files/Scenes/Scene_Map.rb:76:in 'loop'
-Ruby-files/Scenes/Scene_Map.rb:76:in 'main'
-Ruby-files/Initializers/Main.rb:174:in '<main>'
-000:Main:8:in 'eval'
-000:Main:8:in 'block in <main>'
-000:Main:7:in 'each'
-000:Main:7:in '<main>'
- -e:in 'eval'

I have no idea what any of this is, but it's preventing me from entering the game entirely. Please help ;-;