well right off the bat, you set it to use IMAP, not piping
Set it to piping, and you'll see Blesta give you a one line command to enter as an email forwarder in your cpanel account
I don't agree on 777 chmod permissions either. Unless your host is not doing their job correctly. PHP files should never be set to 777 in a cPanel environment. You're just asking to be hacked. 644 for all files, 755 if you really need to.