If you are having problems installing or configuring the ad module, please be
sure to carefully follow the instructions in INSTALL.txt, and to read through
README.txt.

If after reviewing those files you are still having problems with the ad 
module, please review the project's issue queue to see if you are experiencing
a known bug:
   http://drupal.org/project/issues/ad

If you're still unable to find the information you need, you can submit a new
issue by following the above link.  When doing so, it is important that you
offer details on how to duplicate the bug that you are experiencing.  If you
are unable to get ads to appear, be sure to explain what method you are using
to try and display ads: blocks, views, ad_embed, etc...

In the event that ads are not displaying, it is helpful if you collect the
following debug information and inculde it in your bug report.  Using your
web browser, view the html source of the page on which you expect 
advertisements to show up.  Search for the string "serve.php", then copy and 
paste that entire URL directly into your web browser.  It will look something 
like:
  http://sample.com/modules/ad/serve.php?q=1&t=23

Load that URL and see if there are any indications as to why ads are not
displaying.  If not, add "&debug=2" at the end of the URL:
  http://sample.com/modules/ad/serve.php?q=1&t=23&debug=2

(NOTE: you will need to convert "&" to "&" in the url when you cut and
paste it from your html source.  If you do not do this conversion, most of
the URL will be ignored resulting in invalid output.)

You can then submit the resulting debug output in your bug report.