Problems with gd2

Hi!

I’ve installed gd2 on my server (Debian), and I’ve installed the gd2
gem, but i got this problem:

rake db:schema:dump --trace

(in /var/rails/feevy2)
** Invoke db:schema:dump (first_time)
** Invoke environment (first_time)
** Execute environment
rake aborted!
unknown symbol “gdImagePngEx”
/usr/local/lib/ruby/gems/1.8/gems/gd2-1.1.1/lib/gd2.rb:150:in []' /usr/local/lib/ruby/gems/1.8/gems/gd2-1.1.1/lib/gd2.rb:150 /usr/local/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/inflector.rb:250:ininject’
/usr/local/lib/ruby/gems/1.8/gems/gd2-1.1.1/lib/gd2.rb:150:in `each’

Any idea? Thanks!