This is a quick test to try out a couple methods of fixing the proxy authentication issue with the PortableApps.com Platform 2.0 Pre-Release 2.1 release. Please try this two separate replacement files to see if they work. You'll need to download them and rename them to PortableAppsUpdater.exe and replace your existing file in your PortableApps\PortableApps.com directory to try them out. Keep a copy of your existing one to switch back to.
Updated Method: Download The Test Fix - This should resolve the issue fully and only show the banner during startup when required to show the login. It should also resolve the issue of a blank updater page showing. If this does not work for you, please move on to the others...
Download Current inetc Test - This one will leave any files you download behind in Temporary Internet Files on the local PC but will work with both the standard updater/app directory and the check for apps on startup silently feature (except for prompting for password, of course).
Download Banner Test - This one will show a duplicate banner in updater/app directory mode and show a banner in check for updates on platform startup feature (when it shouldn't).
To check the check for updates on startup feature, first enable check for updates on startup in the Options window on the Advanced tab. Then, you can take an installed app like 7-Zip Portable and edit it's appinfo.ini file in the 7-ZipPortable\App\AppInfo directory. Change the line PackageVersion=184.108.40.206 to PackageVersion=220.127.116.11 which will make the updater think there is a new version. Then exit the platform (no need to eject) and then start it again with Start.exe.
Please give this a try if you use a proxy that requires authentication and report back your findings for both updater replacements and for both the updater/app directory and the automatic update check on startup in this thread.
ADDED: Also, if proxy users could post the exact error message they see when they run the standard 2.0 Pre-Release 2.1 updater from the menu (not the automated startup which should produce no error). It should be an error like "Unable to connect to PortableApps.com to retrieve portable apps. Please try again later." in your language followed by an error code within brackets. It's the exact error code within brackets we're interested in. Does everyone get [Proxy Error (407)]? And does it come up just about instantly after running or is there a delay (if so, could you time it)?