shopperpress Stylesheet is missing.

Hi on the themes page at the bottom . I get a warning ” shopperpress Stylesheet is missing.”

I think this might be why I am having so many problems with this theme.

1: A customer paid for a download and it did not show in her back end ( Dashboard )
so I checked it was paid, I just emailed it to her to save time….
2: when I am in the Area “Website Overview” i try to setup ” Setup Listing Pakages & Fields ”
but a new page opens and just says “” You do not have sufficient permissions to access this page. “”
I asume all of this is a problem with my missing stylesheet

I know its probable me doing something wrong

Nick