Installing Drupal

I have checked all help topics for this issue and still havn't solved the problem.
I know alot of people have this issue.

I am using mamp, I created a database, after I go to install db name and user info and select "save and continue"
I get a white screen!!!!
help!!!

Warning: unlink(/tmp/update-cache/856680) [function.unlink]: Permission denied in drupal_unlink() (line 2139 of /home/ldus/public_html/includes/file.inc).

Warning: unlink(/tmp/update-cache/rules-7.x-2.0-alpha2.tar.gz) [function.unlink]: Permission denied in drupal_unlink() (line 2139 of /home/ldus/public_html/includes/file.inc).

Warning: unlink(/tmp/update-cache/ubercart-7.x-3.0-alpha3.tar.gz) [function.unlink]: Permission denied in drupal_unlink() (line 2139 of /home/ldus/public_html/includes/file.inc).

Hi,

I've managed to create Drupal 6.x multisite installations on my shared hosting account (cPanel). I've done this for different domains (e.g. www.example.com, www.example2.com, etc) as well as subdomains (e.g. site1.example.com, site2.example.com).

Here's a simplified explanation for how I usually achieve this.

1. Add the domain or subdomain using cPanel (using Addon Domains or Subdomains respectively)
2. When adding the domain/subdomain I usually choose public_html as a folder. I notice other prefer to create the domain/subdomain folder and then delete it. From my experience either works I just prefer the former option.
3. Create a folder in the SITES folder.
4. Rename the folder to the domain name (e.g. www.example.com or site1.example.com).
5. Copy the default.settings.php file into the folder and rename it to settings.php.
6. Create a PHP symlink.

  symlink( '/home/example.com/public_html/', 'site1' );

7. Go to the domain/subdomain and install Drupal.

All this works fine.

PROBLEM

I now want to create a Drupal installation in a subdirectory (e.g. www.example.com/site1). I've found documentation (http://drupal.org/node/278987) on how to achieve this. I've tried it but am unable to achieve this.

Here are my questions:

I got http 500 internal server error when trying to install drupal 7. any advise what to look for to fix this error?

my server is:
FreeBSD 6.4-RELEASE
php 5.2.5
mysql 5.0.45

I have uploaded Drupal 7 to GoDaddy - apparently successfully - but when I attempt to log into my site the following errors are reported:

Warning: Unterminated comment starting line 5342 in /home/content/76/7118176/html/includes/common.inc on line 5342

Fatal error: fatal flex scanner internal error--end of buffer missed in /home/content/76/7118176/html/includes/common.inc on line 5342

I deleted the comment beginning on line 5342 from common.inc but a new problem arose on a different line.

I am hosting through IX Webhosting and having an install issue. The datbase is not on localhost. I've tried changing the word localhost to my actual DB server name throughout the code. I've tried commenting out the db_url= line in the settings.php and am still getting the following error:

Failed to connect to your MySQL database server. MySQL reports the following message: Access denied for user 'c317894_einstein'@'98.130.2.53' (using password: YES).

Any help on this topic would be appreciated.