I did an oracle 11g 64bit install on my 64bit core 2 quad using the resources available on internet and some past experience.
The tutorial here is great :
However, some things still show up after the initial setup is done. Here are bits of my experience -
1. Starting Enterprise manager after a reboot -
Try emctl status agent
The last line of the output should tell you whats happening. If its not running, start it using the following -
emctl start dbconsole
This thanks to http://www.linuxquestions.org/questions/linux-general-1/linux-5-oracle-11g-enterprise-manager-question-616532/
2. The ORACLE_SID variable must be declared in either /etc/profile (for a single database on the system) or on user's local profile.