I'm pretty sure that won't fix it. This sounds like a save error.
The items are being seen in game perfectly well so that rules out CSV errors. If that were the cause then the items wouldn't be usable at all.
You can do /item 2 2 1 and get a green hat right?
You can buy hats from NPCs right?
If so then your CSVs are fine.
What is happening here is that somehow your items are either being saved to the database incorrectly or they are being read back in incorrectly.
To find out which, take a look at your database entry for a character who was saved with a hat.
The most likely error is that the type is getting scrambled somehow.
Is the hat saved as type 0 or 2?
if it is 2 then it is also saving correctly so the error is in the load function.
if it is 0 then it is saving wrong.
Is there some other strangeness with the save entry?
Does it exist at all? Actually I think it must exist or you would not get the error on loading.
Till you figure this out, we can't go any further with diagnosing the real problem. Just do this test then report back and i will see if I can figure it out for you.
