i have vps with 512ram

i install on my server but script get more memory , plz tel me how i control it ?

try to disable mysql innodb extension, refer to mysql docs for this.

additionally,
kill all mysql processes, then,
/etc/init.d/mysql restart

this will free some memory.
after that,
restart ehcp
/etc/init.d/ehcp restart

I have a VPS with 512mb of ram and no issues (5 Customers). What is the exact error you are getting? And if you don't mind me asking what vps provider are you using?.