Welcome to the Q&A Forum

Directories are a good starting point for link building especially for a new site.    However, you have to be very selective as to which directories you submit to.  The oldest and most relevant are Yahoo directory, Best of the Web, DMOZ, (good luck with that) We have a very select list of less than 25 we will initially submit to.   That's it for directory submission. You will need to diversify your linking strategy moving forward.

I am also getting this error.  However, the site/server is online.

We have detected that the domain www.houston-montessori.com does not respond to web requests. Using this domain, we will be unable to crawl your site or present accurate SERP information.

I have run into this with several domain I am trying to setup.  Is there an issue with the crawler?