directory set error, now cannot access admin tool

I installed wordpress for the first time today and all went well and it installed with a MySQL db (with 100mb capacity).

Then I started browsing the virgin admin area and got to a screen where I was allowed to set the directories which are to be considered the main blog location. There were two directories to set. I forget now what they were titled or what was or is in them now, but the second one said “make this different if you want your blog to be in a directory different from your main index.html”. Since this is exactly what I want to do (I want to have the blog machinery live in a directory under root called ./blog/ not under root ./ where index.html lives) I put in this ./blog/ postfix on this admin setting page.

This is a fatal error for myself because now I can no longer access the admin area because (I think?) it is looking in ./blog/ for machinery which is actually currently in the original ./blog/wordpress/ area.

So I then FTPd all the wp-xxx.php txt files back over to my laptop so i could view their contents and find out in which of the 24 files the PATH is set. I did find that in wp-load.php the following takes place:

define( ‘ABSPATH’, dirname(__FILE__) . ‘/’ );

And this variable ABSPATH is in fact used everywhere as a prefix, and since he is getting loaded by __FILE__ then I need to know where __FILE__ is being loaded but I cannot find it in any of the 24 files.

Does anyone know where this __FILE__ is set so I can remove the ./blog/ postfix with a txt editor on my laptop, then FTP the file back over to the hosted blog so as to get back into my admin tool so as to reset those main directories back to normal?

Next, which or how many files must be moved from the ./blog/wordpress/ folder up into the ./blog/ folder so that I can in fact reset the main blog location directory to be ./blog/ as actually desired?

In sum, Right now my tree is:

mainURL/ this is where index.html lives
mainURL/blog/ this is where I want the wordpress machinery
mainURL/blog/wordpress/ this is where wordpress machinery lives

Finally, after I succeed in setting up all of that, I want to use the THESIS THEME but a search on the WordPress home page with those keywords does not take me to a page that says “download Thesis Theme” or even to anything which says “This is what Thesis Theme” is. Why if themes are so important to WordPress is a well known theme named Thesis not in any list of Themes?