Reset PHP Error before running included script - php

Question

I am combining two existing scripts to built something new and safe time by using existing code:
php_simple_html_dom to parse some html
the wp-db.php class from wordpress to access the database
These two scripts don't play nicely along. I used xdebug to find out that the main problem was caused in this piece of code in php_simple_html_dom:
if (($error=error_get_last())>null) {
$this->clear();
return false;
}
Because the wordpress template I use fires some E_NOTICE level errors this results in my php_simple_html_dom getting cleared.
The weird thing is, I do not include any template code as I include and instantiate wp-db.php myself like this:
require_once('../wp-config.php');
require_once('../wp-includes/wp-db.php');
$wpdb = new wpdb(DB_USER,DB_PASSWORD,DB_NAME,DB_HOST);
Even when I step through the code completely with xdebug it never hits anything else from wordpress then wp-config.php or wp-db.php.
Edit:
As indicated by horatio, this actually does get called from the
include of wp-settings.php in the end of wp-config.php. I now
understand why my debugger never hit it: netbeans had failed to
download wp-settings.php so it could not debug it.
Nevertheless this is the error returned by error_get_last():
Array
(
[type] => 8
[message] => Undefined index: id
[file] => (real-path-deleted)/wp-content/themes/supermassive/lib/inc/options.php
[line] => 10
)
I think I could solve this problem using one of two different strategies:
1. Stop the unneccessary wordpress code that is causing the errors from running.
Reset the error returned by error_get_last() before php_simple_html_dom is run.
Which of these would be the best and how would I go about to achieve it?