Installing Drupal

OK folks, it's been over 4 years since the last time I did this, so it's going to take me some time to get back up to speed!

Hi everyone, I am a web developer, but new to drupal. I just designed a client's site with drupal. Now the problem is this, the drupal work fine on my workstation, I want to upload the site to his host, but this is what I got:
PDOException: SQLSTATE[HY000] [2002] Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2) in lock_may_be_available() (line 165 of /home/coursono/public_html/includes/lock.inc).

Hi

My name is Mark and I am novice with drupal...

I'm trying to find a way to post blog content from my drupal site to my facebook and twitter account.
Searching with no result through many modules I decided to create this forum topic...

Does anyone have a clue how I ca realize that?

Regards
Mark

i have downloaded drupal 7 into file system/home/lim/drupal
i tried to copy the directory into file system/var/www
i typed sudo cp home/lim/drupal var/www i was told "No such file or directory"
then i typed sudo cp drupal /var/www i was told "omitting directory 'drupal' "
am i missing something?

I need to understand more about searching for a specific contributed module to install on my demonstration site.

I have an instance of Drupal 7 in my top-level domain -- it works fine.

I have installed Drupal 7 in a sub directory -- for testing purposes.

When I try to access TLD/sub/install.php
the top-level Drupal captures the request
and I get the error message:
"The requested page "/sub/install.php" could not be found."