curb gem installation: bundle install fails, but n

Question

solved: the openvz container did not have enough memory assigned to it.

I could need some help: I want to install the curb gem through bundler.

My config (please request more details if needed):

ruby 1.8.7 (2010-08-16 patchlevel 302) [x86_64-linux]
gem 1.8.6
Bundler version 1.0.15
Linux 2.6.32-5-openvz-amd64 #1 SMP x86_64 GNU/Linux
cat .bundle/config 
--- 
BUNDLE_DISABLE_SHARED_GEMS: "1"
BUNDLE_PATH: vendor

A normal install works:

gem install curb
Building native extensions.  This could take a while...
Successfully installed curb-0.7.15
1 gem installed

But it does not work via the bundler gem:

bundle install
Fetching source index for http://rubygems.org/
Using rake (0.8.7) 
Using builder (2.1.2) 
Using bundler (1.0.15) 
....
Installing curb (0.7.8) with native extensions /usr/local/lib/site_ruby/1.8/rubygems/installer.rb:551:in `build_extensions': ERROR: Failed to build gem native extension. (Gem::Installer::ExtensionBuildError)

        /usr/bin/ruby1.8 extconf.rb 

Gem files will remain installed in /xxx/vendor/ruby/1.8/gems/curb-0.7.8 for inspection.
Results logged to /xxx/vendor/ruby/1.8/gems/curb-0.7.8/ext/gem_make.out
    from /usr/local/lib/site_ruby/1.8/rubygems/installer.rb:504:in `each'
    from /usr/local/lib/site_ruby/1.8/rubygems/installer.rb:504:in `build_extensions'
    from /usr/local/lib/site_ruby/1.8/rubygems/installer.rb:180:in `install'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/source.rb:101:in `install'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/rubygems_integration.rb:78:in `preserve_paths'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/source.rb:91:in `install'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/installer.rb:58:in `run'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/rubygems_integration.rb:93:in `with_build_args'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/installer.rb:57:in `run'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/spec_set.rb:12:in `each'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/spec_set.rb:12:in `each'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/installer.rb:49:in `run'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/installer.rb:8:in `install'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/cli.rb:222:in `install'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/vendor/thor/task.rb:22:in `send'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/vendor/thor/task.rb:22:in `run'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/vendor/thor/invocation.rb:118:in `invoke_task'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/vendor/thor.rb:246:in `dispatch'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/lib/bundler/vendor/thor/base.rb:389:in `start'
    from /usr/lib/ruby/gems/1.8/gems/bundler-1.0.15/bin/bundle:13
    from /usr/bin/bundle:19:in `load'
    from /usr/bin/bundle:19

gem_make.out contains only one line:

cat /xxx/vendor/ruby/1.8/gems/curb-0.7.8/ext/gem_make.out
/usr/bin/ruby1.8 extconf.rb 

Running extconf.rb manualy creates the Makefile without warning. Running make, also shows no warnings.

I would be very happy if you could help me on this or give a hint on where to look for errors.

Thanks