n my solution for the fontconfig issue, I am not talking about replacing any files. Only copy them in Second Life's directory.
For example, assuming you have Second Life in your home directory, like this:
/home/YourUserName/SecondLife
In there, you place the files:
libfontconfig.so
libfontconfig.so.1
libfontconfig.so.1.4.4
and then run Second Life.
Now, your case looks like a different issue. Did Second Life run OK in a previous Ubuntu version, at the same computer?