Which file is PostgreSQL log file 0?
That would be 000000010000000000000001 or 000000020000000000000001. That's timeline 1 or 2, log 0, segment 1. Which one is being accessed depends on which timeline your system in (you can use pg_controldata to find that out, but basically the system switches timeline when you do a PITR recovery or a replication failover)

The error message basically says that file is corrupt, which is really bad. Another reason this could happen is if that file is from a different version of postgresql - any chance you accidentally mixed two different versions?