I don't know what your issue is, but it might have something to do with your KoL Options/Inventory settings. (account.php?tab=inventory)
Make sure you turn ON inventory images.
I had the same issue here what I did
1. uninstall all WTF scripts
2. go into the 'relay' folder and delete all 'wtf' files ( i found three files were left [ wt.ash wtf.css wtf_sortable.js] )
3. in the 'options' tad in the main KoL interface window. go to Inventory -> uncheck show inventory images -> recheck inventory images
4.close relay browser
5 .click on the Graphical CLI tab in the Mafia control panel. This will show you if you have fix the issue
6. pop up the script Manager and reinstall wtf_Inventory . watch the Gr CLI,if you've done things right, youll see mafia downloading alot of files
7.wait for mafia to finish downloading things
8. open relay browser
9.while watching GR CLI, click on the Inventory icon. If you've done things right you should see no error messages
10. What I did was repeat steps 4 thru 9 for the rest of 'WTF 'scripts . I did this to make sure the other Wtf scripts were not what was causing the issue
edit: This issue happen after I updated to Mafia r19380 and lost all pref setting