Hi, i`ve seen this with a couple of customers before in the past and it generally happens when there is a temporary blip in the initial download of the mirror.
go into c:\program files\alwil software\management tools\mirror and manually kick off mirror.exe
this will pull down any missing files and update the mirror.
At first It didn’t work.
The mirror.exe tried to connect to avast servers, but it wasn’t downloading the files.
So I guessed it could be a block police in my proxy server.
After that I put an exception on the proxy server to grant access to “avast.com”, it started to work, downloading the necessary files.
After it downloaded all files from avast mirror, everthing went just fine to create the packaged.
It’s strange that when installing ADMN, there was no error on mirror creating due to the proxy blocking.
I think that routine in installation must present an error to the user if mirror cannot download files.