Sorry for the newbie question. I am new to nginx. i installed it successfully on my mac, but when i try to start it, i get this error

nginx: [alert] could not open error log file: open() "/opt/local/var/log/nginx/error.log" failed (13: Permission denied)
2011/11/20 22:15:20 [emerg] 1620#0: open() "/opt/local/etc/nginx/nginx.conf" failed (2: No such file or directory)

Can someone please help me resolve this? Thank you

Kofi