There was a PTR patch yesterday morning, so that's the update you're seeing.
If you're running an Anti-Virus or Firewall program, can you try disabling it
and then running the Launcher again?
Alternatively, you could create another admin account
on your system and attempt to run the Launcher from there.
If those don't solve the issue, could you please send me a copy of your most recent Battle.net Logs?
This may not result in an immediate fix for your individual issue, but it will go directly towards getting this sort of issue fixed in general. That being said, if we can find anything in the your logs that will help us to better troubleshoot your issue, we will do so.
You can navigate to the folder by following these steps:
· Configure Windows to Show Hidden Files and Folders
, as the ProgramData
for Windows XP) folder is normally hidden.
· Navigate to the folder containing the Battle.net
· Windows XP: C:\Documents and Settings\All Users\Application Data\
· Windows Vista or later: C:\ProgramData\
Then can you attach the log files from the following folders: c:\ProgramData\Battle.net\Agent\Agent.1637\Logs\
(If you have it, or the highest incremental number you have.)
And please also include this file as well:c:\ProgramData\Battle.net\Agent\agent.db
You can email those as a zip archive to this address: firstname.lastname@example.org
Please use this line for the subject: [Apollo] [Can't download patch] 
After you send those files, you could also attempt to Delete the Battle.net folder
and then re-run the Launcher and see if that helps to resolve the issue.