This article explains why myisamchk returns error 140 when you try to run it.
Resolution
From LMI 6.2.0 onwards, a change in the MySQL version installed means that the myisamchk syntax has changed. You should now specify the file without the .MYI extension, as below:
Logapp root:/loglogic/data 1$ myisamchk -r -f /loglogic/data/ll_www_logs/mrgWWWLOG_0 - recovering (with sort) MyISAM-table '/loglogic/data/ll_www_logs/mrgWWWLOG_0' Data records: 0 - Fixing index 1 - Fixing index 2