Extension Activation

After a handful of installs, uninstalls and a current 10.6_1 (revision 1 on 10.6) on El Capitan (OS X), I can’t seem to get one extension working:

mydb=# CREATE EXTENSION IF NOT EXISTS htore;
ERROR: could not open extension control file "/usr/local/Cellar/postgresql(at)10/10.6_1/share/postgresql(at)10/extension/htore.control": No such file or directory

However, it does exist:

$ /usr/local/Cellar/postgresql(at)10/10.6_1/share/postgresql(at)10/extension] ll hstore.control
-rw-r--r-- 1 rich admin 158B Feb 6 23:17 hstore.control

I don’t think this is a homebrew error (the package manager I used to install PostgreSQL), but I’ve informed them.

Is there anything that anybody sees here that I’m doing wrong? I’ve tried single quotations and double quotations around ‘hstore’ and I get the same error. Other extensions install properly.

Any advice appreciated.