Thank you for replying, I fixed the problem by using a newer client.
..but also considering going back to 2012-04-10 once I get to know what's wrong.
Additional information on the 2014-04-10 client::
I've tried with ID 25000 - 30000 but still no luck, wearing the costume still kicks me out.
Putting the data on db\import-tmpl\item_db.txt just gave me more unknown sprite errors and kicks me out
