I get the following message when I try to upload a License.config file through the new user interface for licenses:

/EPiServer/CMS/Admin/SiteInfo.aspx

Communication with license service failed:
An item with the same key has already been added.

2010-01-14 17:24:43,763 ERROR [7] EPiServer.Licensing.SiteInformationHandler.UploadLicense - Error uploading license
System.Configuration.ConfigurationErrorsException: An item with the same key has already been added.
   at EPiServer.Licensing.SiteInformationHandler.ValidateAndSaveConfiguration(Configuration configuration)
   at EPiServer.Licensing.SiteInformationHandler.UpdateSiteSetting(String siteId, String siteUrl, Int32 startPageId, String licenseFilePath, IList`1 siteHosts)
   at EPiServer.Licensing.SiteInformationHandler.HandleContentFile(SiteInformation siteInformation, Byte[] licenseContent)
   at EPiServer.Licensing.SiteInformationHandler.UploadLicense(String siteId, Byte[] licenseContent, Boolean throwException)
2010-01-14 17:24:49,795 WARN [PipeServerChannel.ServerMain] Microsoft.Samples.Runtime.Remoting.Channels.Pipe.DBG.Warning - 18.3.1 Scheduler error:  Terminating client connection: Error reading from pipe 3540: error 109

Trying to request demo license gives a similar error:

2010-01-14 17:25:54,809 ERROR [7] EPiServer.Licensing.SiteInformationHandler.GetDemoLicenseInfo - Error getting demo license
System.Configuration.ConfigurationErrorsException: An item with the same key has already been added.
   at EPiServer.Licensing.SiteInformationHandler.ValidateAndSaveConfiguration(Configuration configuration)
   at EPiServer.Licensing.SiteInformationHandler.UpdateSiteSetting(String siteId, String siteUrl, Int32 startPageId, String licenseFilePath, IList`1 siteHosts)
   at EPiServer.Licensing.SiteInformationHandler.HandleContentFile(SiteInformation siteInformation, Byte[] licenseContent)
   at EPiServer.Licensing.SiteInformationHandler.GetDemoLicenseInfo(String siteId, Boolean throwException)