I have a similar problem. After launching "public/steambootstrapper_english.txt". error appears in my terminal and then small Steam updater (similar to the one from windows), but with ugly fonts. Even those in wine are better. 
Then the updater extracts some files (png, tar etc. ) to the directory with steam.sh and disappears with the second line printed in my terminal (the one with 1352224866_client error).
Another thing is it created new and empty folder called 'Steam' in my home directory. (my steam.sh is in /home/programs/steam_beta/steam.sh)
Code:
> ./steam.sh
ILocalize::AddFile() failed to load file "public/steambootstrapper_english.txt".
Installing breakpad exception handler for appid(steam)/version(1352224866_client)
> echo $?
255
//Running 12.2 (64) + Gnome 3.4
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