Which Wolfram Language version are you using? It looks like this notebook was originally created in 13.0. If you are attempting to use in 13.1 you need to update it. You should be prompted to automatically update it the first time you press any button. Select “OK” from this dialog.
It will take a few seconds to update then it should work. If you hit “Cancel” on the dialog once, then you should save it, close it, reopen it and hit “Check” again. Then you will get the prompt again.
A Wolfram Function Repository reviewer was able to fix the issues with your submission notebook, with the fixed notebook attached to this reply. The reviewer also commented the following:
“The current function name feels wrong, since Series and TimeSeries are totally different things in the system. This function should be renamed to something like FractionalDTimeSeries, since it acts on TimeSeries objects.”
Just for the record: Frank’s submission seems to have gone through okay (I was working with him via an internal ticket), including the proposed name change.
I’ll be sure to monitor this thread moving forward to see if Frank runs in to any other issues, etc.