@tashburn, I guessing your tying to use the HTTP Header method of authenticating with Splunkd. Your access-token is your session key which can be used against the API, which can be retieved from the /services/auth/login and will be a long string of hexadecimal chars.
curl -k -u <user>:<passw> https://<splunkd>:8089/services/auth/login \ -d username=<user> -d password=<passw>
<response>
<sessionKey>##someHexdecimalNumber##</sessionKey>
</response>
Additional info:
REST API Overview - Auth Methods
Hope this helps.