This helped when I changed the hostname on my mysql slave server:

Here is a sample error message:

060614 11:17:42 Error reading packet from server: Could not find first log file name in binary log index file (server_errno=1236) 060614 11:17:42 Got fatal error 1236: ‘Could not find first log file name in binary log index file' from master when reading data from binary log

https://web.archive.org/web/20160502185939/http://dev.mysql.com:80/doc/refman/5.0/en/replication.html

Neohapsis Archives – MySQL Discussion – #2000 – Re: weird replication problem with master.info being created empty