Module leads to white screen and error messages

Hi, I've installed the module and enabled it. However, when I update settings.php, I get a white screen with the follwing two statements:

Warning: require_once(./sites/all/modules/no_anon/session-no-anon.inc) [function.require-once]: failed to open stream: No such file or directory in C:\Inetpub\drupal-6.17\includes\bootstrap.inc on line 1141

Fatal error: require_once() [function.require]: Failed opening required './sites/all/modules/no_anon/session-no-anon.inc' (include_path='.;C:\php5\pear') in C:\Inetpub\drupal-6.17\includes\bootstrap.inc on line 1141

I'm really not sure what the above mean. Am I doing something stupidly wrong, or is there something else I need to adjust?

Many thanks,

chaz1975