I had this same issue with my Droid 1....I was going to try widget locker on this phone bc I don't like the lockscreen on here. the market tells me that its purchased so when I click install it tells me I need to purchase it. I called Android market support and they show me buying it in September but that he couldn't help me trouble shoot bc i'm rooted and that me being rooted is what messed my market account up.
If anyone had any ideas id appreciate it.
Nvm I got it. I just installed updates and bought it again. Hope this helps anyone else.