Plot Style problem in DS2018SP2

I have downloaded the latest version of DS2018SP2 but I am unable to change, create or edit the plot style configuration. I have downloaded and installed DS several times but to now avail. I have a older copy of DS2018 (SP1 I think) on another laptop and this works fine, I can add/edit 'cfg' and 'ctb' files in there, but not on SP2. Is anyone else having this problem? Or know of an answer please?