Pretty sure I had the same problem (Error code A12E1)
As I recall I cleared the browser cache and just waited a little while and tried again and it worked just fine
Cleared browser cache via F5.
Tried both Mycroft Internet Explorer & Firefox & received the same error message.
I notice in the Window Task Manager that the Adobe Application Manager (AAM) did appear as a 32bit application. I have a 64 bit computer. The AAM died about ¾ of the way thru the down load. A little passed after I gave the permission to continue the load to the OS.
No error code appeared on the screen.
I'm going to write this information cause it was so darn frustrating and after two days I finally got it - so here goes - resolution:
I'm running windows 7, and was trying to download cloud which apparently I was forced to do based on my subscription base (was on CS6 before that)
Step 1: start task manager and close ALL adobe running apps including akami session
Step 2: click on the windows icon and type in search bar %appdata%, enter
Step 3: in browser bar above of folder, click on "appdata" (my file directory when i typed step two was C:\Users\study\AppData\Roaming, and I need to be be at C:\Users\study\AppData)
Step 4: Click Local, then Adobe, then oobe, delete the oobe file
Step 5: Go the the following to download the "cleaner tool": http://download.macromedia.com/pub/creativecloud/cleanertool/win/Adobe_Creative_Cloud_Clea ner_Tool.zip
Step 6: Unzip the file and click on the AdobeCreativeSuiteCleanerTool.exe, that was in my directory as follows (dependent on where you download and unzip of course) C:\Users\study\Downloads\adobe_creative_suite_cleaner_tool (1)\win
Step 7: select (e) in the black box for "english", select (y) for yes, select creative cloud (whichever option # that is) and again anything with creative cloud (this did NOT delete my other adobe files, which I feared may - but I was simply instructing it to clean/delete the creative cloud.
Step 8: close the black window
Step 9: Click here: http://www.adobe.com/support/downloads/detail.jsp?ftpID=4773 and download the creative cloud adobe application manager
Step 10: Run the application
Step 11: Log in and download the software you want
If that doesn't work, what I did is between steps 4 and 5 I restarted my computer, then I went into task manager and closed all adobe apps. I'm not sure I had to do this step but I was desperate after 2 days doing whatever. Each tech person gave me different information. The last person helped me best, but I spoke with her via chat AFTER I had rebooted the computer. If you need support click http://helpx.adobe.com/contact.html and I personally did the "chat" so I wouldn't have to wait.
Hope this helps anyone who hasn't figured it out!