Heat oil in a medium sized pot with a lid over medium heat. Add garlic, bell pepper and onion, cook until they are slightly caramelized. Add hamburger meat, salt & pepper to taste, and cumin, brown meat until almost cooked through. Add canned diced tomatoes, corn, including their liquids, add squash and water or stock if more liquid is necessary. Bring to a boil on medium high and then reduce heat to low. Cover and simmer 15 minutes or until meat is completely cooked and the squash is softened.