Apache Crashing every few days on Linode 512

message

Mar 24 12:31:36 li279-200 kernel: Out of memory: kill process 26468 (httpd) score 58140 or a child
Mar 24 12:31:36 li279-200 kernel: Killed process 26468 (httpd)
Mar 24 12:31:59 li279-200 kernel: mysqld invoked oom-killer: gfp_mask=0x201da, order=0, oom_adj=0

HTTPD logs

[Wed Mar 23 11:41:21 2011] [notice] caught SIGTERM, shutting down
[Wed Mar 23 11:41:32 2011] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Wed Mar 23 11:41:32 2011] [notice] Digest: generating secret for digest authentication ...
[Wed Mar 23 11:41:32 2011] [notice] Digest: done
[Wed Mar 23 11:41:33 2011] [notice] Apache/2.2.17 (Unix) DAV/2 PHP/5.3.5 configured -- resuming normal operations

MySQL Config

key_buffer = 16M 
max_allowed_packet = 64M 
thread_stack = 192K 
thread_cache_size = 4
max_connections = 50 
table_cache = 1000 
table_definition_cache = 1000 
thread_concurrency = 12 
query_cache_limit = 1M 
query_cache_size = 12M

httpd conf (Just changed this)

 <ifmodule prefork.c="">StartServers       5
MinSpareServers    5
MaxSpareServers    5
ServerLimit      256
MaxClients       25
MaxRequestsPerChild  1000</ifmodule> 
KeepAliveTimeout 2