hi all, i have a problem syncing my files onto my iphone.

when i connect my iphone, itunes will open up and detect it. then it'll start backing up and sync the bookmarks and applications. after that it states "syncing xxx's iphone" then it will like suddenly disconnect with my iphone.

my iphone will still have the "sync in progress" sign but my itunes does not show my iphone. after a while i remove the cable but the musics and photos that i tried to sync are not in there.