look at dan stylez posts here: https://www.phpbb.com/customise/db/exte ... pic/221026
there is alink to download the extension from github that apparentlly works and then lower you can download new copies of the styles folder for prosilver and for elegance styles to fix the problems.
keep in mind that these arty styles are no longer updated or supported in any way by arty.
a couple of people have taken up some of them to keep the udated but I would suggest you find some different styles
because you never know if they are going to be updated/upgraded in the future.