the only reason it didn't save a x file is you probably didn't add the x extension, it doesn't do it automatically..
Also by default it wont save to the entity folder in GG you need to set the permissions
I notice it had issues with long texture names, some of the new Sketchup textures don't save BUT it also fails with other export formats
If its warehouse models failing, well, they can be a bit rubbish, you need to do stuff like check the faces are pointing the right way
It works perfectly fine here, as long as the texture names are short, you add the extension ~~(you can add it later anyway) and save it were you have rights its fine,