To Resolve the above error, follow the steps below:
Browse to your server _Docs folder where you should find a case icons folder. In there you will have a selected folder containing icons associated with each case type. There will probably be two set up for the same case type.
They are made up of three sets of numbers - the first set of numbers is the case type number - the second set is the image number and the last is either 32 or 16 for the resolution. If you sort them, you should have no more than 2 per case type number - if you have more then remove the ones you don’t want to use.