You could try
uname -a to see if it also mentions x86_64 or not, but I think it probably gets the information from the same place as
As a shot in the dark/straw grasp, does
ldd sublime_merge mention any libraries that might be missing? I would expect not because that's usually a different error, but it may shed some light on things.
Similarly you could check and see that the binary has executable permissions, but it should come out of the tarball that way and I'd expect something like a "Permission Denied" error in that case.