So it's obvious that you have files permissions issue. It's hard to tell why you don't have an access. Maybe you've extracted EPESI with a different user than the http server user, so server can't read the files. There are sometimes specific restrictions for direct script execution like execute flag, or readable only by http server user. You should look up your hosting help, faqs or contact support to fix privileges.
Error from thread title may be caused by file privileges. I'm pretty sure that some part of Javascript isn't transferred to your browser. It may be file permissions issue, but also template cache issues.
Steps that I would make to fix this:
1. delete all files in <epesi dir>/data/cache/minify (do not delete this dir)
2. Fix all file privileges. Whole EPESI dir with data dir has to be readable and writable by http server user. (I prefer using shell access, ftp is slow and hard to use.)
3. Go to admin tools <epesi url>/admin/ - log as super admin. You should see several menu entries that we will use later. Run actions:
a. "Rebuild common cache & default theme"
b. "Rebuild language files"
4. Clear browser's cache again.
Regards,
Adam
