Help using an array to display posts

I am working on a custom theme for an existing wordpress install. It uses a Favorites plugin that allows people to bookmark their favorite posts. The plugin includes a function that allows you to get the IDs of the bookmarked posts for a logged in user. If you output that array, you get something like Array ( [3] => 6309 [4] => 6411 [5] => 6408 )

I am trying to use that with query_posts(), but it’s not working. I’m guessing this is because the array contains the keys? If so, how do I work it so that it’s not a problem. If it’s not, could someone give me some direction? Sorry, I am still trying to wrap my head around arrays :/