I tried a number of different options to try to get this to work. Dug up a post on setting 1.6.7 to use dynamic URLs & paths to try to enable the CP in my local dev environment:
When I was still unable to log in, I ended up following this advice:
Generally it helps to change admin part to session only or cookies
only, I like session only but it seems some hosting companies have
session encrypted and that can cause problems. Also, in Chrome I have
extension for cookies, so I delete cookies when such things happen.
And second problem I can have is when I do test, login to test without
a problem, go to production, and cannot login or when I go from one
client to another on another server only because I opened different
CPs several times.
Try that ... change session only or cookies and session to cookies
only or vice versa, delete browser cache and try again OR of you do it
several times and it does not work, wait for few minutes.
Simply clearing the cache & deleting cookies did not work. I had to change the following from:
$conf['admin_session_type'] = "c";
$conf['admin_session_type'] = "s";
Then I was able to log in.