I'm a SLACKWARE 12.2 user. I've installed Cinelerra but it needs the libmp3lame.so.0 in order to run. I've already downloaded that library, but I don't how to get it installed. This is the message I get from my terminal:

cinelerra: error while loading shared libraries: libmp3lame.so.0: cannot open shared object file: No such file or directory

http://bogdan.org.ua/2007/06/30/libm...-lame-397.html - you need to install Lame.

There's a SlackBuild for lame:
http://slackbuilds.org/repository/12.2/libraries/lame/
Read the Howto, or get sbopkg to make SlackBuilding easier & quicker:
http://www.sbopkg.org/

Ok, I've installed lame, and some other pkgs I found out that were missing. Yet there's still some pkgs to be installed. Unfortunatelly, I couldn't find half of them anywhere yet. Do you lot have any idea where to get them from?

ldd /usr/bin/cinelerra

libfaad.so.0 => not found
libfaac.so.0 => not found
libx264.so.56 => not found
liba52.so.0 => not found
libIlmImf.so.6 => not found
libImath.so.6 => not found
libHalf.so.6 => not found
libIlmThread.so.6 => not found
libIex.so.6 => not found
libsndfile.so.1 => not found
libFLAC.so.7 => not found
libavc1394.so.0 => not found
librom1394.so.0 => not found
libdv.so.4 => not found
libmjpegutils-1.9.so.0 => not found

And why I couldn't install the following ones?

# cd libiec61883
root@tgklohn:/home/tklohn/Drivers/Undone/libiec61883# ./configure
bash: ./configure: File or directory not found
root@tgklohn:/home/tklohn/Drivers/Undone/libiec61883# make
make: *** No indicated target and no make file found. Stop.

# cd libraw1394
root@tgklohn:/home/tklohn/Drivers/Undone/libraw1394# ./configure
bash: ./configure: File or directory not found
root@tgklohn:/home/tklohn/Drivers/Undone/libraw1394# make
make: *** No indicated target and no make file found. Stop.
root@tgklohn:/home/tklohn/Drivers/Undone/libraw1394#

For a start, install some packages from http://www.slackbuilds.org. I am not sure about special order, but such should be stated on the site.

libsndfile
faad2
faac
a52dec
x264
ilmbase
mjpegtools
libavc1394 (for libavc and librom)
libdv

As you see in most cases guessing the name of the package you need is not that hard. The search function on www.slackbuilds.org takes also incomplete packages names and you don't need wildcards - "mjpeg" as search term leads you to mjpegtools for example.

Thanks very much,Tito! Nevertheless, I still haven't figured out why my ./configure command doens't work. I read all the readable files within the pkg I want to install but there's nothing on how to install it.

Take a look, for example, at the attempt of installation of this pkg for Cinelerra:

root@tgklohn:/home/tklohn/Desktop# tar -zxvf mjpegtools.tar.gz
mjpegtools/
mjpegtools/mjpegtools.info
mjpegtools/README
mjpegtools/mjpegtools.SlackBuild
mjpegtools/slack-desc
root@tgklohn:/home/tklohn/Desktop# cd mjpegtools
root@tgklohn:/home/tklohn/Desktop/mjpegtools# ./configure
bash: ./configure: File or directory not found
root@tgklohn:/home/tklohn/Desktop/mjpegtools#

With slackbuild-scripts you don't run ./configure yourself. You just execute programname.SlackBuild (in your example mjpegtools.SlackBuild) and be sure to download the source of your desired program and not just the SlackBuild-script.
The usage of slackbuild-scripts is explained here:
http://www.slackbuilds.org/howto/

greets
m.

You also need to download the source tarball (in this case, mjpegtools-1.9.0.tar.gz) into the mjpegtools directory.
Abraço.

You're well on your way to a disaster with your Frankenstein linux installation that used to be Slackware.
You're trying to mix binary packages (with apparently undocumented dependencies) from one place with locally compiled dependencies and self-compiled binary packages from SlackBuilds.org and probably binary packages from other places, and it's only a matter of time before you really screw the pooch.

If you install package A from somesite.com, then somesite.com had better document all of package A's dependencies AND provide them, or else you should RUN away from somesite.com - if not, they're going to screw your system sooner or later.