Memory exhaust on 5 node site - more

When istalled CONTENT_ACCESS module, I received this error message:

Fatal error: Allowed memory size of 31457280 bytes exhausted (tried to allocate 361919 bytes) in C:\wamp\www\res\includes\database.mysql.inc on line 380

Warning: Table 'watchdog' was not locked with LOCK TABLES query: INSERT INTO watchdog (uid, type, message, severity, link, location, referer, hostname, timestamp) VALUES (1, 'php', 'Table 'sessions' was not locked with LOCK TABLES\nquery: SELECT sid FROM sessions WHERE sid = '35b8f6500c0a14c8bc6da14181a64c9b' in C:\\wamp\\www\\res\\includes\\database.mysql.inc on line 172.', 2, '', 'http://localhost/res/admin/build/modules/list/confirm', 'http://localhost/res/admin/build/modules', '127.0.0.1', 1208939688) in C:\wamp\www\res\includes\database.mysql.inc on line 172

Warning: Table 'watchdog' was not locked with LOCK TABLES query: INSERT INTO watchdog (uid, type, message, severity, link, location, referer, hostname, timestamp) VALUES (1, 'php', 'Table 'sessions' was not locked with LOCK TABLES\nquery: INSERT INTO sessions (sid, uid, cache, hostname, session, timestamp) VALUES ('35b8f6500c0a14c8bc6da14181a64c9b', 1, 0, '127.0.0.1', 'form|a:7:{s:32:\\"c2c524e5827d79b8d64f483fdaa118ff\\";a:2:{s:9:\\"timestamp\\";i:1208888914;s:4:\\"args\\";a:1:{i:0;s:14:\\"system_modules\\";}}s:32:\\"9113b262fed175cdfaf60d67ebbd5893\\";a:2:{s:9:\\"timestamp\\";i:1208888935;s:4:\\"args\\";a:2:{i:0;s:24:\\"system_modules_uninstall\\";i:1;a:5:{s:9:\\"uninstall\\& in C:\wamp\www\res\includes\database.mysql.inc on line 172

I'm not anterily clear about that message, but size of memory allowed is 10times bigger then size tried to allocate...??

I have found similar problems, but just on big sites. My site has at the moment about 5 nodes!!

Any suggestions..? Thank you..