PHP Warning – Failed to open stream: Permission denied.

Most likely you have very restrictive permissions set for your WordPress directories.
The recommended permission for folders are 755 and for files 644

Some reference links –

1. WordPress.org forum – http://bsf.io/f-0yo
2. StackOverFlow – http://bsf.io/0at-g
3. How to change permissions – http://bsf.io/pcxrg