RMagick LoadError

Hello,
I installed "rmagick-1.15.12-x86-mswin32" gem, but when I try to start
the WEBrick server, I get this error:

C:/Ruby/lib/ruby/gems/1.8/gems/rmagick-1.15.12-x86-mswin32/ext/RMagick.so:
126: Can not find the specified module. -
C:/Ruby/lib/ruby/gems/1.8/gems/rmagick-1.15.12-x86-mswin32/ext/RMagick.so
(LoadError)
from C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:32:in
`require'
from
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-1.4.1/lib/active_support/dependencies.rb:495:in
`require'
from
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-1.4.1/lib/active_support/dependencies.rb:342:in
`new_constants_in'
from
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-1.4.1/lib/active_support/dependencies.rb:495:in
`require'
from
C:/Ruby/lib/ruby/gems/1.8/gems/rmagick-1.15.12-x86-mswin32/lib/RMagick.rb:11
from C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:32:in
`gem_original_require'
from C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:32:in
`require'
from
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-1.4.1/lib/active_support/dependencies.rb:495:in
`require'

It's work on console script. Can anyone help me?

Thanks,
Jero

Run/Debug Configurations:
RubyScript: D:\ProjectRoot\script\server
Choose Server: WEBrick
Port: 3002
IP Address: 127.0.0.1
Server Arguments:
Environment: development
Environment Variables:
Ruby arguments: -e "STDOUT.sync=true;STDERR.sync=true;load($0=ARGV.shift)"
Choose Ruby SDK from module: ruby1.8.6