Hi to all, I'm installing ROOT analysis program on a machine with Fermilab SL v. 3.0.3 . I cannot install it because the package "X11-devel" is not installed. So i tried to install this package using the visual tool "Add/Remove package" included in distribution. I guess that it is in the "X11 Develepment" package group, but i cannot install it because there are some missing dependancies that cannot be found (isn't strange that there are packages without their dependancies?!?!?). So i looked for the RPMs present in the installation CDs and i found (in the 2nd CD): XFree86-devel-4.3.0-68.EL.i386.rpm The problem is that the installed X11 version is 4.3.0-81, i.e. it is newer that the one on the installation CDs (and also using command line "rpm" fails because of missing dependances or newer versions), so i guess that there a sort of "automatic update tool" on the distribution. I discovered that this tool is "yum", in fact there is always a cron process running it. In the How To of the SL site, i found instructions about using this "yum", but i cannot execute on a shell "yum" because there is already another "running yum" in background. How can i add this "X11-devel" package and all its required dependances? Consider that i'm not the pc owner, so all i do must be safe. I thank you in advance Matteo Alfonsi