[ruby-list:46772] google-appengine について

北村と申します。
環境は、Ubuntu 9.10で、ruby1.9.1p376です。
Google App Engineでのアプリケーション作成で、google-appengineのgemを使おうとしたのですが、
まず、

require 'appengine-rack'
AppEngine::Rack.configure_app(
  :application => 'mailtter'
  :version => '0.5'
)
run lambda{ Rack::Response.new('Hello, world!')}

という内容のconfig.ruを作成し、

$ dev_appserver.rb .

のコマンドを打つと、

=> Booting DevAppServer
=> Press Ctrl-C to shutdown server
file:/usr/local/lib/ruby/gems/1.9.1/gems/appengine-jruby-jars-0.0.6/lib/appengine-jruby-rubygems-0.0.6.jar!/rubygems.rb:280:in
`activate': can't activate bundler (~> 0.7.2, runtime) for
["appengine-tools-0.0.7"], already activated bundler-0.8.1 for []
(Gem::LoadError)
	from file:/usr/local/lib/ruby/gems/1.9.1/gems/appengine-jruby-jars-0.0.6/lib/appengine-jruby-rubygems-0.0.6.jar!/rubygems.rb:296:in
`activate'
	from file:/usr/local/lib/ruby/gems/1.9.1/gems/appengine-jruby-jars-0.0.6/lib/appengine-jruby-rubygems-0.0.6.jar!/rubygems.rb:295:in
`each'
	from file:/usr/local/lib/ruby/gems/1.9.1/gems/appengine-jruby-jars-0.0.6/lib/appengine-jruby-rubygems-0.0.6.jar!/rubygems.rb:295:in
`activate'
	from file:/usr/local/lib/ruby/gems/1.9.1/gems/appengine-jruby-jars-0.0.6/lib/appengine-jruby-rubygems-0.0.6.jar!/rubygems.rb:68:in
`gem'
	from /usr/local/bin/appcfg.rb:18
Error executing jruby
2010/01/14 12:43:23
com.google.apphosting.utils.config.AppEngineWebXmlReader
readAppEngineWebXml
致命的: Received exception processing
/home/yutaka/Dropbox/Mailtter/WEB-INF/appengine-web.xml
com.google.apphosting.utils.config.AppEngineConfigException: Could not
locate /home/yutaka/Dropbox/Mailtter/WEB-INF/appengine-web.xml
	at com.google.apphosting.utils.config.AppEngineWebXmlReader.getInputStream(AppEngineWebXmlReader.java:102)
	at com.google.apphosting.utils.config.AppEngineWebXmlReader.readAppEngineWebXml(AppEngineWebXmlReader.java:60)
	at com.google.appengine.tools.development.AbstractContainerService.loadAppEngineWebXml(AbstractContainerService.java:204)
	at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:118)
	at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:217)
	at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:162)
	at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:48)
	at com.google.appengine.tools.development.DevAppServerMain.<init>(DevAppServerMain.java:113)
	at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:89)
Caused by: java.io.FileNotFoundException:
/home/yutaka/Dropbox/Mailtter/WEB-INF/appengine-web.xml (No such file
or directory)
	at java.io.FileInputStream.open(Native Method)
	at java.io.FileInputStream.<init>(FileInputStream.java:137)
	at java.io.FileInputStream.<init>(FileInputStream.java:96)
	at com.google.apphosting.utils.config.AppEngineWebXmlReader.getInputStream(AppEngineWebXmlReader.java:99)
	... 8 more
com.google.apphosting.utils.config.AppEngineConfigException: Could not
locate /home/yutaka/Dropbox/Mailtter/WEB-INF/appengine-web.xml
	at com.google.apphosting.utils.config.AppEngineWebXmlReader.getInputStream(AppEngineWebXmlReader.java:102)
	at com.google.apphosting.utils.config.AppEngineWebXmlReader.readAppEngineWebXml(AppEngineWebXmlReader.java:60)
	at com.google.appengine.tools.development.AbstractContainerService.loadAppEngineWebXml(AbstractContainerService.java:204)
	at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:118)
	at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:217)
	at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:162)
	at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:48)
	at com.google.appengine.tools.development.DevAppServerMain.<init>(DevAppServerMain.java:113)
	at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:89)
Caused by: java.io.FileNotFoundException:
/home/yutaka/Dropbox/Mailtter/WEB-INF/appengine-web.xml (No such file
or directory)
	at java.io.FileInputStream.open(Native Method)
	at java.io.FileInputStream.<init>(FileInputStream.java:137)
	at java.io.FileInputStream.<init>(FileInputStream.java:96)
	at com.google.apphosting.utils.config.AppEngineWebXmlReader.getInputStream(AppEngineWebXmlReader.java:99)
	... 8 more

と出力されてエラー終了し、正常に動きません。
どなたか解決法をご教授ください。