Table keeps being damaged

[maxwolf]

I'm running mySQL 3.22.27.
A table in my DB contains 190,000 entries.
The table is accessed aproximately by 1.48 users a second.

Every 5 - 15 minutes the table gets damaged, so that
isamchk -a table1 returns:
- check record links
isamchk: error: Wrong bytesec: 0-0-0 at linkstart: 12202079
ISAM-table '/usr2/mydb/table1' is corrupted
Fix it using switch "-r" or "-o"

isamchk -o fixes the problem,
but it appears again after max. 15 minutes!

Is there smth. wrong with mySQL server configuration?
How can I avoid this problem (without scheduling cron to
run isamchk every 7 minutes).

Thanks!

BTW: the server configuration file (my.cnf) looks following:
# The MySQL server
[mysqld]
port = 3306
socket = /tmp/mysql.sock
user = mysql
skip-locking
set-variable = key_buffer=16M
set-variable = max_allowed_packet=1M
set-variable = thread_stack=128K
set-variable = max_connections=300
set-variable = table_cache=128
set-variable = back_log=64

[mysqldump]
quick
set-variable = max_allowed_packet=16M

[mysql]
no-auto-rehash

[isamchk]
set-variable = key_buffer=16M