I get the error: The item cannot be listed or modified. The title and/or description may contain improper words, or the listing or seller may be in violation of eBay policy.

eBay bans certain words and phrases, this can result in a listing being refused. eBay recently made a change to its policy regarding offline payments, you can no longer accept personal checks or money orders for listings on eBay and you listings can not contain any text stating you accept these payment methods.

Ensure that within your seller information tabs that you have not entered any reference to money orders, personal checks or made any claims about your status such as "top rated seller". If you have, you must remove this before amending any of your live listings.

Also ensure that the items you are trying to apply the design have more that 24 hours remaining before they expire, as you cannot revise an item that expires within 24 hours.