GRAVITY FORMS CORRUPTING THE DATABASE TABLES

Hello,
I have gravity forms Version 1.6.4.5 installed in a multiuser WORDPRESS site environment.Suddenly my mysql database just died,and I had to kill mysql processes manually to restart it. I did the mysql repair from the command line and it works for a while,after which the tables get corrupted again.
These are some of the tables that keep getting corrupted:

>>>># myisamchk /var/lib/mysql/domain/*MYI >/tmp/myisamchk.log
myisamchk: warning: Table is marked as crashed
myisamchk: error: Found 4533 keys of 4532
myisamchk: error: Recordlink that points outside datafile at 176108
MyISAM-table '/var/lib/mysql/domain/555_27_rg_lead_detail.MYI' is corrupted
Fix it using switch "-r" or "-o"
myisamchk: warning: Table is marked as crashed and last repair failed
myisamchk: warning: Size of indexfile is: 73728     	Should be: 1024
myisamchk: error: Recordlink that points outside datafile at 556968
MyISAM-table '/var/lib/mysql/domain/555_27_rg_lead.MYI' is corrupted
Fix it using switch "-r" or "-o"
myisamchk: warning: Table is marked as crashed
myisamchk: error: Found 2229 keys of 2228
MyISAM-table '/var/lib/mysql/domain/555_28_rg_form_view.MYI' is corrupted
Fix it using switch "-r" or "-o"
myisamchk: warning: Table is marked as crashed and last repair failed
myisamchk: warning: Size of indexfile is: 23552     	Should be: 1024
myisamchk: error: Record-count is not ok; is 227      	Should be: 0
myisamchk: warning: Found    	227 parts            	Should be: 0 parts
MyISAM-table '/var/lib/mysql/domain/555_sitemeta.MYI' is corrupted
Fix it using switch "-r" or "-o"

The wordpress is Multiuser install, 555 is database prefix and the other number is the MU site number. Now when the repair is done to the database tables, it works a bit and get corruptzed again.The following tables get corrupted:
rg_lead
rg_lead_detail
rg_form_meta
rg_form_view
rg_form
Any idea what is causing this?