Loading config file

Hi, I hope someone can help me with this. I have just build a Geeetech Pruse i3 pro b, all working fine, but I am having an issue with Slic3r. Repetier does not appear to recognise the printer (no info on Slic3r page) and I cannot load a plane config file. The g code appears fine, but of course without all the PLA parameters the print is rubbish. I am using an iMac os version 10.14.6. Thanks.

Apologies I forgot to add - I get this message when I try to load the file:
Wx::ComboBox:etSelection at /private/var/folders/1j/s7chyccn4vsfbvmklgyd68x00000gn/T/AppTranslocation/5FCED5B6-3EBF-448A-B214-9AF44195C5DB/d/Repetier-Host Mac.app/Contents/Resources/Slic3r.app/Contents/Resources/lib/std/Slic3r/GUI/Tab.pm line 844