If the lamp is flickering, like trying to ignite, but doesn't quite, its usually the starter. As the other post states, it's the cylinder thing. The cream thing is probably just the wiring bridge, which isn't involved aside from providing a connectionnto the mains. The white metal thingy is the ballast, doesn't usually need replacing. As LEDs replace the fluorescent tubes, you will find it harder to find parts, so you might just want to replace the whole fixture with something led based.