/usr/bin/php5-cgi high load and 500 erro

[xchrix]

hello

i have som problems with my virtual debian server. nearly every day i get a 500 error on php sites then i have to restart the whole server. nothing works anymore. ssh is dead, ftp, email..

in the apache error logs i always see this errors/warnings

Code:

[Fri Jul 04 17:15:18 2008] [warn] FastCGI: (dynamic) server "/var/www/fcgi/kunstkalender.org/php5-fcgi-starter" (pid 5225) termination signaled
[Fri Jul 04 17:15:19 2008] [warn] FastCGI: (dynamic) server "/var/www/fcgi/kunstkalender.org/php5-fcgi-starter" (pid 5225) terminated by calling exit with s$
[Fri Jul 04 17:16:18 2008] [warn] FastCGI: (dynamic) server "/var/www/fcgi/kunstkalender.org/php5-fcgi-starter" (pid 31953) termination signaled
[Fri Jul 04 17:16:18 2008] [warn] FastCGI: (dynamic) server "/var/www/fcgi/kunstkalender.org/php5-fcgi-starter" (pid 31953) terminated by calling exit with $
[Fri Jul 04 17:17:18 2008] [warn] FastCGI: (dynamic) server "/var/www/fcgi/kunstkalender.org/php5-fcgi-starter" (pid 3833) termination signaled
[Fri Jul 04 17:17:18 2008] [warn] FastCGI: (dynamic) server "/var/www/fcgi/kunstkalender.org/php5-fcgi-starter" (pid 3833) terminated by calling exit with s$
[Fri Jul 04 17:18:18 2008] [warn] FastCGI: (dynamic) server "/var/www/fcgi/kunstkalender.org/php5-fcgi-starter" (pid 25846) termination signaled

what means this? when i get the 500 errors i have error logs which are like "cannot allocate memory" this is because i have not much memroy on my virtual server what shall i do?

i have the newset ispcp version installed.
thank you[/code]