/join #gentoo-ops and ask for voice. Feel free to ping an op there, we may not notice your join.

Some of the more popular #gentoo- channels are listed here

/msg mzbot faq xorg

expat-2.0.1 is not ABI compatible with earlier versions. Run the following in bash to fix:

emerge -n1 '>=portage-2.1.2.12' portage-utils && emerge -qep world | grep --color=never -oFf <(scanelf -plRBF '%F %n' | awk '/libexpat.so.0/{print $1}' | xargs qfile -qC | sort -u; echo -e "libtool\ncurl") | xargs emerge -1

If a specific package fails, (gtk+/pango are common). If, while trying to fix the expat mess, a package won't build then run the following (substituting "gtk+" with the name of whichever package that failed):

emerge -n portage-utils && grep -vxFf <(emerge -qep system) <(emerge -qep gtk+) | sed -rne '/^\[ebuild/{s/(^| )\[[^]]*\]( |$)//gp}' | xargs qatom | awk '{print $1"/"$2}' | xargs emerge -1". 

Afterwards, run

 emerge --resume 

to continue.

expat-2.0.1 has been marked stable, but it is not ABI compatible with earlier versions. To fix, we recommend running

 "emerge portage-utils gentoolkit && emerge -1 $(qlist -qICe expat gettext python XML-Parser dbus apr apr-util fontconfig libXft) && revdep-rebuild --library libexpat.so.0". 

If gtk+ then fails, run

 
 "emerge -C gtk+ pango cairo && emerge -1 gtk+ && emerge --resume".
 

Some packages, usually pre-compiled binary packages such as mozilla-firefox-bin, are written in C++ and are only compatible with the C++ runtime library provided by gcc-3.x. If this is the case then you can avoid having to install gcc-3.x entirely by installing libstdc++-v3 beforehand

emerge -1 sys-libs/libstdc++-v3

which provides the library without the whole gcc ... continue with your emerge that failed

As of coreutils 6.10 mktemp is included directly in the coreutils package. Just unmerge mktemp to resolve this blocker.

xorg-x11-7.3 is not yet supported by the official ati-drivers packages and, hence, are blocked. If you are affected and wish to continue using the official drivers, then you should mask the newer version of xorg until ATI rectify the situation

echo -e "=x11-base/xorg-server-1.4*\n ~x11-base/xorg-x11-7.3" && /etc/portage/package.mask.

KDE 4.0 is in the portage tree, hard-masked. You can get help in #genkdesvn and #gentoo-kde after reading http://xrl.us/bekfz. Please do not ask about kde 4 in #gentoo.

Recently installed sys-libs/db-4.5* and having problems building apr/apr-util? To fix,

emerge -C apr-util apr

then

emerge -1 libtool apr-util"

Just ask, don't ask to ask, don't ask who's familiar. Don't ask if anyone knows about it.

Just ask the question, it's the easiest way to get people to answer :)

To inform us about a problem, you need to give us the /fault/, not the error.

Error lines that begin with "!!!" or "make" are of no use to us. Fault lines, like "foobar.o: no such file or directory" or "undefined variable cabli" are.

If it is over a few lines, please use a pastebin such as http://rafb.net/paste/

Portage is Gentoos' software management system, built to provide as much flexibility as possible. It uses ebuilds as package format and supports both source code packages (most used) and binary packages (such as GRP). See parts 2 and 3 of the Gentoo Handbook

Paludis is an alternate package manager. It is not an official gentoo project, so for help you should go to #paludis or its home page

pkgcore is an alternative package manager. It is not an official Gentoo project. You can get help at here or on freenode at #pkgcore