In Winamp 2.64 (not sure about 2.63), the "Play | Bookmark" menu seems to get confused if you add more than 2 bookmarks and edit some of the bookmark titles.
For example, my Winamp has 5 bookmarks. All of them are Shoutcast URLs. At first, I leave the bookmark titles as they are, like "http://220.127.116.11:7501/", and the "Play | Bookmark" menu looks fine.
But after I have edited some of the bookmark titles so I'll know which bookmark is which station, I start to notice that the "Play | Bookmark" menu now displays 3 repeats of one of the bookmarks, and 2 repeats of another bookmark.
This bug only appears in the "Play | Bookmark" menu. The "Bookmarks" menu works fine.