Wordpress Permalinks issues on Amazon EC2
AMAZON EC2 INSTANCE TRICKS
Your server may not have the AllowOverride directive enabled. If the AllowOverride directive is set to None in your Apache httpd.config file, then .htaccess files are completely ignored.
To fix it go to /etc/httpd/conf then open http.conf by running vi httpd.conf and then change "AllowOverride None" to "AllowOverride All":
You may also need to change AllowOverride here:
# AllowOverride controls what directives may be placed in .htaccess files.
# It can be "All", "None", or any combination of the keywords:
# Options FileInfo AuthConfig Limit
Important! Restart httpd by running service httpd restart.