Default base paths are auto generated based on $_SERVER[’SCRIPT_NAME’].
Do you run windows? What error message did you get when you tried to proceed with backslashes?
yep running windows (wamp). i didnt get an error message at all when attempting to just proceed with backslashes. it just seemed to reload the page each time i tried. when i changed both basepath and secure base path (http and port 80) to foreward slashes it went through fine (although i first ended up with pdo exception errors on the next screen:
[message:protected] => SQLSTATE[42S02]: Base table or view not found: 1146 Table 'magento.usa_postcode' doesn't exist
[code:protected] => 42S02
[file:protected] => D:\wamp\www\magento.dev\lib\Varien\Db\Adapter\Pdo\Mysql.php
[line:protected] => 106
[trace:private] => Array
etc etc etc
when i reloaded THAT page, it seemed to continue and finish the database population. i assume i probably just need to set a longer timeout.