I looked in extracted SCS file files for the c1 folder in automat. It is there, but doesn't have the file that the error says (starts with a3e). I tried adding the whole c1 folder but it didn't work.
The folder names (like c1, c2 etc.) seem to organise the files by their first two letters of the name if that makes sense, so all the files inside the c1 folder start with "c1". I looked inside the a3 folder to see if the material was in there but it doesn't seem to exist.
The problem may be something to do with using ETS2Studio as it has not been updated in a long time, so maybe it is creating the mod for an older version of ETS2? It's a trailer mod so should work with any version but maybe it is trying to use a file which doesn't exist anymore?
How do you change the version of the SCS uploader? I tried rightclicking then properties but I can't find anything to change the version.
And yes it works fine without the workshop. It;s not important to get it on the workshop it's just my first time doing it and would like to try
Thanks for your time