ok, it's gotta to be a small setup problem somewhere I didn't do right. I removed everything else besides zimbra stuff (actually I didn't add the others, they came with the package), then it still gave me the same problem, I know I can start it using zmcontrol and it ran fine:
zimbra 23700 1 10 13:36 pts/4 00:00:06 /opt/zimbra/jdk1.5.0_05/bin/java -Xms303m -Xmx303m -client -XX:NewRatio=2 -Dcatalina.base=/opt/zimbra/jakarta-tomcat-5.5.7 -Dcatalina.home=/opt/zimbra/jakarta-tomcat-5.5.7 -Djava.io.tmpdir=/opt/zimbra/jakarta-tomcat-5.5.7/temp -Djava.library.path=/opt/zimbra/lib -Djava.endorsed.dirs=/opt/zimbra/jakarta-tomcat-5.5.7/common/endorsed -classpath /opt/zimbra/jakarta-tomcat-5.5.7/bin/bootstrap.jar:/opt/zimbra/jakarta-tomcat-5.5.7/bin/commons-logging-api.jar org.apache.catalina.startup.Bootstrap start
so it's gotta to be my eclipse setup that's not right, missing classpath or something ? I set up the preference for Tomcat according to tim's setup and I added Build Path/User Libraries with zimbra-*.jars. what else can you think of ?