The metacity --replace is a convention used by window managers (e.g. kwin, compiz, metacity, etc.) which means to kill the existing window manager and replace it with the calling window manager.
My first attempt to utilise the opensource paradigm and (hopefully) get help on/from LQ :-) :-)
Another great part of the open source paradigm is free and frequent updates
Fedora 8 has been around for a while, and it might turn out to be worth it to install that over FC5 (a collateral benefit will be a fresh start). Just be sure to back up your files in advance