Error when configuring Field for content type.

Whenever I try to configure a field in a content type, it will not save any changes beacause it returns something along the lines of:

The default value PHP code returned an incorrect value
Expected format :

array(
0 => array('value' => value for value),
// You'll usually want to stop here. Provide more values
// if you want your 'default value' to be multi-valued :
1 => array('value' => value for value),
2 => ...
);

Returned value :

The 0 => and 1 => change depending on the field type. The error above is from a simple text box.

I am using Drupal 5.7 on Apache 2.2.6 with PHP 5.2.5.

Note: I'm running this on my Windows box w/ XAMPP. I plan to upload it to a remote host when I complete the site.

Thanks for your help.