Issues starting Postgres server I'm trying to go through the book "7 Databases in 7 Weeks" and I'm completely stuck at starting a Postgres server.

My current issue is that when I run pg_ctl start I get the following error:

LOG:  database system was shut down at 2013-06-12 17:18:24 PDT
LOG:  invalid magic number 0000 in log file 0, segment 1, offset 0
LOG:  invalid primary checkpoint record
LOG:  invalid secondary checkpoint record
PANIC:  could not locate a valid checkpoint record
LOG:  startup process (PID 1454) was terminated by signal 6: Abort trap
LOG:  aborting startup due to startup process failure


I have no idea how to go about fixing this. I'm running PostgreSQL 9.2.4 on Mountain Lion 10.8.3.
Per JimmyStenke's suggestion, I realized I had a DB initialized from a previous install, and it seems that was causing the error. I deleted it and initialized a new DB.