Recently i experienced this issue and thought of blogging it.
we were using adodb for database abstraction and had enabled logging.
The error that was given by adodb was like
"LOGSQL Insert Failed : insert into adodb_logsql ..." i have not put the entire SQL there and "Incorrect key file for table yyy.MYI; try to repair it". yyy is a fictional table name.
In this case the server was running linux and the file system had a 2GB limit for a file.

