This error is caused by missing 32-bit libjpeg libraries.https://www.codeweavers.com/support/wiki/diag/missinglibjpeg
new installs of Ubuntu 12.04 64-bit this can be a little tricky to
solve. Crossover needs libjpeg62, but by default on 12.04 64-bit this
library is not available.
To install, download the "libjpeg62_6b1-2ubuntu1_i386.deb" package from here:
and open this package in Ubuntu Software center. You'll probably be told
that it's already installed, but choose to "re-install" anyway. When
this is complete, you should find the following libraries in place:
and the WoW launcher should actually render and work.
Alternatively you can run this command:
sudo apt-get install libjpeg62:i386
ia32-libs packages does not depend (yet) on this and they really don't tell users much about their distro's multi-arch goodness