Well I searched everywhere I could find anything related on otland, and no one has ever even helped someone with opcode errors for otclient. Since Evil Puncker said it was bad items.otb, I would suggest that it, is exactly what it is, you say you replaced the old one... you are replacing on both the client and the server right? Because from as far as I can tell, the problem seems to be relating to a creature that doesn't exist.... you said you only altered outfits, are you sure you don't have a creature using one of the altered outfits? It is very important that when you make changes to an items.otb, that you replace the one being used by the client, the server, and the map editor, all of them... otherwise errors will occur, if you have exhausted all other posibilities... start over... redownload the server, and put it in a different location, different folder for the time, do the same with the client, copy over your config.lua from YOUR server, to the fresh one you just downloaded, start it up, and try to login with the fresh downloaded otclient, if no errors, good! Then you can start transferring other things over to the fresh copies and keep starting until you find the error (don't delete anything) , once you have gone through and added everything from your server, to the fresh copy, and it is still starting fine, then viola, problem is gone... if not, then you know the last changes you made are what is causing the problem.
Please read carefully everything I wrote, and first start with making sure all items.otb are same exact versions, if that fails then try the rest, until you have isolated the problem, at any point, if your problem is solved, please share here what exactly solved your problem, so others can hopefully be helped by finding this thread if they have the same problem.
