Welcome to Linuxquestions.org Mipia,
You shouldn't need to be afraid to reboot, Linux doesn't do spontaneous selfdestruction :-]
About logging. In general there's two ways of logging: to the screen and to files (and the one doesn't exclude the other). The actual logging is done by a program called syslog. Syslog will run until shutdown. So chances are some of the errors you saw will be in the (plaintext) file /var/log/messages. Read it using your favourite editor or in an Xterm run "less /var/log/messages".
If you are not able to install rpm's in X, you could fall back to using a terminal window like Xterm (or Konsole or whatever you are familiar with).
Start with logging enabling logging: "script install.log".
Any messages displayed on screen are now also in the file called "install.log", which you can reread or post parts of if necessary.
Now you will need to check if you've got the dependencies in place. If you haven't, install those first.
There are at least two ways to show dependencies. One is listing them for the rpm: "rpm -q -R -p <rpmfile>" , another is just test-installing the rpm: "rpm -ivh --test <rpmfile>" or test upgrading it from a previous version: "rpm -Uvh --test <rpmfile>".
If the test succeeded without errors, remove the "--test" flag from the commands to install/upgrade.
Another way to upgrade rpm's is to use the Red Hat Network up2date service, but you need to apply for an account (basically free) first. Up2date will handle downloading and installing (most) dependencies as well.
When you're done testing/installing/upgrading, type "exit" to get out of your script session. Reread or save the text file "install.log" if necessary.