Melt butter in a Dutch oven over medium heat; cook 2 minutes or until lightly browned. Add onion and next 7 ingredients (through celery); cook 4 minutes, stirring occasionally.
Increase heat to medium-high. Add chicken broth and vegetable blend. Combine 1 cup water and flour, stirring well; stir into broth mixture. Bring to a boil. Reduce heat, and simmer for 18 minutes. Add crab, and simmer for 2 minutes. Serve over rice.