Is the item available as part of a set? (Sometimes it wont recharge you if you download the set)
What region is your game (Because I'm in North America and i have had no problems with my DLC this time)
A theory i thought of is you might be able to get around this by redownloading the DLC on a different LBP title, cause it seems to give you all 3 versions for a DLC per download --- Little King of LBP Level Recordings http://www.youtube.com/user/JHKthree
I had this too but found it was because I didn't buy the individual costumes I bought the pack, Example: Toy story costume pack, It said Buzz was unavailable but I went and simply downloaded the pack with buzz in it and it bought all of them in LBPK.
I always check the DLC packs and individual DLC thing you spoke of. Thanks to the both of you for posting. Semi-panicked since I bought all the DLC for LBP2. --- "If I kept it any more real, physics as we know it, would cease to remain the same."