Problem with Gummi: Compilation Program is Missing

For some reason Gummi doesn't seem to search PATH and adding the texlive directory to it doesn't work, so ...

Rather than copying the binaries across as the accepted answer suggests, just create symlinks to all the binaries in your texlive directory, substituting 2012 with whatever your version of TeX Live is:

• 32 bit:

  sudo ln -s /usr/local/texlive/2012/bin/i386-linux/* /usr/local/bin/
  

• 64 bit:

  sudo ln -s /usr/local/texlive/2012/bin/x86_64-linux/* /usr/local/bin/
  

You need to create links to all the binaries (i.e. not just pdflatex), as otherwise some documents would fail to compile.

The website troubleshooting says on section "Gummi won’t start or load correctly after an upgrade.":

Gummi won’t start or load correctly after an upgrade.¶

Try to remove the files snippets.cfg and gummi.cfg that are located at /home/[{your-username}]/.config/gummi. Removing them will have Gummi re-create the default configuration when it is next started, so don’t forget to back them up if you want to retain your configuration.

So when you have installed TeXLive new delete both old snippets.cfg and gummi.cfg to get new on for using with TeXLive 2012. Because gummiis under development install the actual version (today: Gummi 0.6.4 (June 24th, 2012)).

If Gummi still can't found the compilation program you can try to copy pdflatex executable to /usr/local/bin and run it again. (If you have still problems a reboot could help.)