Tomcat 3.2.4 / JDK 1.4.1 crashes

Help please....I've developed a mysql, jsp, servlet, web site which has been fine for months and now crashes occasionally. So far I thought of memory and disk space... So we recently increased the memory (from 512mb to 2Gb) but it still happens. There is loads of disk space Nothing is appearing in the tomcat log files, any clues to how can I find out what is happening? is there a mac os x log that might give some clues? Thanks Neil :?: