I thought this was a problem with using a different version of Ruby to
the version that the extension (Ferret or RMagick or whatever else)
was compiled with. Ferret 0.10.9 was compiled with 1.8.4-20 and it
sounds like you tried that so now I'm confused, especially since it
didn't work when you tried building the extension yourself.
Unfortunately I can't replicate the error here, otherwise I might be
able to fix the problem. Could you tell me, does this cause an error
on your system?
irb(main):001:0> require 'rubygems'
irb(main):002:0> require 'ferret'
irb(main):003:0> "\t\t\t\t Hello".dump
=> "\"\\t\\t\\t\\t Hello\""