This is a known issue with Up2Dates larger than 100MB. If your Astaro has 512MB or less, you cannot upload the file manually. The automatic download by the Astaro works just fine.
You might try to do this from the command line and let us know if that works (2009-AUG-12: I did this last night, and it worked perfectly):
And you also need to run 'auisys.plx --showdesc' or the new package will not be shown in the webadmin as 'available for installation'. If you use the regular up2date downloader, the webadmin upload, or if you install the up2date from the console, you don't need to do this. Cheers, andreas