Train Sim World 3 Class 158 Northern Rail

Hi, I dont know if you can help and unfortunatly I am not on discord server. I cannot now import liveries. I am hoping that someone who uses Raging lightning's TSW3 Livery Manager can possibly suggest a solution to my problem. Other people must be using it so I am assuming that something is wrong. The old version used to work but since I have installed the new version (following a reinstalltion of TSW3) I cannot get it to work. I can correctly identify the directories (set library/ set game) and import files but when I click on Save it does not work and produces the error message: "[Err] Unable to save liveries. Object reference not set to an instance of an object" . I am ok with file structures but fairly clueless with coding! Can anyone suggest a practical solution to try that might work. I am assuming that I cant just 'paste' the livery files somewhere? Any help would be greatly appreciated. Thanks