Affected versions: All
Affected platforms: All

Issue:
When clicking "Next" on the Licensing Activate page, the following error appears:

Solution:
There are two possible solutions to this problem:

1. Make sure that the Web server user has write access to the filestore.
The Web server user can be:

•   Unix / Mac systems: www / daemon / nobody
  
•   Windows: IIS_<MachineName> and/or IIS_WPG
  

2. Make sure that the value length of the ATTACHMENTDIRECTORY option in the config.php file is not too long.
You can make use of symbolic links on Unix/Mac systems to shorten it