This is because there's a weird error with Ruby interpreters on some MAC's...
The loader file Sketchucation.rb tries to set up the ' TEMP' folder as it loads.
But as a fallback it currently uses Dir.pwd to set at least some folder if the other more likely folder-paths fail.
We will remove this in the next update of the toolset, even if the MAC error is not fixed, as it was a bit 'belt-and-braces' and that path was very very unlikely to be needed.
Here's a fix you can make before we issue an update, note that because if will break the current 'signing code', you will need your Extension Manager > Loading Policy set to 'Unrestricted' to let it load properly...
Open the file ../Plugins/Sketchucation.rb in a plain-text-editor [not a wordprocessor].
Find line #60 and edit that, and line #61 below it...
It originally says:
'/tmp', Dir.pwd
change it to read:
'/tmp'#, #Dir.pwd
with two added # symbols to stop the text following them being read...