Looks like 3.0.1 on Windows 8.1. The most common thing that is a problem there is some kind of firewall.
I looked at the files and I see erl.exe failing to start. One reason that could happen is if there is an old erl.exe running still from one of the earlier installs. I’d recommend stopping the Couchbase Service and then verify there is no erl.exe running. If one is still running, kill it and then start the Couchbase Service.
If that doesn’t help, let me know and I’ll ask some other folks to have a look at the logs.