Apparently something went wrong with logrotate.
Are you able to rename the file using mysql user? You should be. If not:
[LIST]
[]Does the user for logrotate exist and is the password set correctly? For example on Debian the user is debian-sys-maint and the password should be set in /etc/mysql/debian.cnf.
[]Does the file belong to mysql user and mysql group? Is it writeable by the owner? (if not, it should)
[/LIST]