I seem to be having trouble with the widgets on my samsung moment. Everytime I download a widget from the market it never shows up when i long press the home screen and look under widgets. Any help is appreciated, Thanks. Nick
Not sure how you are trying to add it to your homescreen but I too had problems at first so here is the way to add it.
Go to menu>add> and pick one of the choices, I am assuming you are picking widgets so pick widgets and pick the one you want and if you don't have enough room on the homescreen,(widget may be too big) then it won't let you add it. I had to remove several icons I had so that my widget would fit.
Hope this helps.