There is more to film production than just a producer with a load of money, for starters one needs a script in order to make a film. This is where the lowly scriptwriter jumps into action. While many scriptwriters get short end of the script in terms of financial compensation without them there would be no basis for a film. Many films that are based on previous works, such as books or comics, must jump through additional financial hoops in order to become established for film production. Ownership must be established and royalties must be paid out in order for a movie like Spiderman get the green light.
While scriptwriters may have the thought and insight to create a film's narrative they usually lack knowledge in the legal process. This is when the lawyers and agents come in. These scumbags scoop up profit from the real artists, forcing them to lose a part of their soul.
The most important person (in my book) is the producer. This person is the star of the show, the bee's knees, captain of the football team! The producer pulls the project together, coordinating with everyone from the scriptwriters to the directors. He/she is responsible for attaining film cast and crew (through hiring of casting directors) as well as the equipment. Some producers are cool, making films like National Treasure, while others are sellouts making crap like three variations of the same show. Just kidding, that was Jerry.