Perhaps the ballasts' ignitor is fried... Can you successfully fire other bulbs with that ballast?
What about trying that lamp on another ballast?
Does the lamp look clean or dirty on the inside?
Can you see the tabs inside the lamp? They're about the size of a thumbtack head just outside the inner bulb. Some lamps have 1, some have 2 - not sure on the Hamilton until I go home and see my old ones. They should be clean and shiny. If not, they may not function properly and cause your problems.