Is there a 64 bit version of Andromeda 5 by XS software? Or a 64 bit client for the same game?
I have created a username and password, then downloaded the setup package, and everything worked well. This was tested on Windows 10 X64 operating system. It's also possible that you're using an older version of the launcher that doesn't support 64bit computing.
Use the following link to download the program: http://asset.andromeda5.com/setup/Andromeda5Setup.exe