When using absolute paths with extracting zips to the store directory you will get error for "Could not create directory " (Which is at line 224 of functions_compress:

										trigger_error("Could not create directory $folder");

). note the $folder in the error.
because of $folder is empty it cant create the directory.
This indirect also means that the first / isnt appended to the $str, what causes that it also cant open the zip later.
The class should check if its absolute path and prepend a first /.