Hi,
I believe you introduced a major bug in 2.2.0. If width is 0% (which is a valid usecase, sometimes the progress bar is still empty), your wppb_get_progress_bar function interprets that as empty and throws an exception.
The exception triggers a PHP Fatal error. Meaning every site that uses this plugin, and has a page with an empty progressbar, completely breaks.
Please have a look, if you have the time.
Regards,
Anna