"Another transaction by user ..." prompt while uploading appengine source

Problem Occurred:

Unable to update app: Error posting to URL: https://appengine.google.com/api/appversion/create?app_id=allenpettle324&version=1
409 Conflict
Another transaction by user allenshao.android is already in progress for this app and major version. That user can undo the transaction with appcfg.py's "rollback" command.

?

Using appcfg command to resolve this problem.

D:\Development\GAE\appengine-java-sdk-1.4.3\appengine-java-sdk-1.4.3\bin>appcfg.
cmd --email=allenshao.android@gmail.com --passin rollback D:\Development\WifiHot
spotSearch\war
Reading application configuration data...
2011-5-3 21:41:52 com.google.apphosting.utils.config.AppEngineWebXmlReader readAppEngineWebXml
信息: Successfully processed D:/Development/WifiHotspotSearch/war\WEB-INF/appengine-web.xml
2011-5-3 21:41:52 com.google.apphosting.utils.config.AbstractConfigXmlReader rea
dConfigXml
信息: Successfully processed D:/Development/WifiHotspotSearch/war\WEB-INF/web.xml
2011-5-3 21:41:52 com.google.apphosting.utils.config.IndexesXmlReader readConfigXml
信息: Successfully processed D:\Development\WifiHotspotSearch\war\WEB-INF\appeng
ine-generated\datastore-indexes-auto.xml
Beginning server interaction for allenpettle324...
0% Rolling back the update.
Success.
Cleaning up temporary files...