It's not exactely obvious what's going on .. I would change
using (var directory = GetDirectory())
to
using (var directory = GetDirectory(@"C:\Some-Directory\Indexes", true))
in the index creator, ensure indexes ARE being generated, then when you know the indexes are being created, use that same directory eg
using (var directory = GetDirectory(@"C:\Some-Directory\Indexes"))
in the 2nd piece of code that uses the indexes
There was one example I saw here
Create and retrieve informations from an index with Lucene.NET – Tier-1[
^] that may help