AWS error "Failed to load private key!"

i have an Amazon AWS account, and it working fine. i had to change my domain, and moved all the account to the new domain, and now i cant get signed URL anymore, keep getting the error "Failed to load private key!". i created a new key pair, and uploaded it, but no success as well.

even the simplest script, as downloaded from amazon: http://ift.tt/1JJ7ldf is not working. (and i did change to my secret key and the right url where the key is)

I am hosting my domain on ipage. any ideas?