I accessed
http://<server>/includes/connect.php directly, and the blank browser screen appears again. I tried in Netscape and Opera as well, just to make sure this was not an IE quirk, and the same behavior persists.
I did not change the directory structure internal to phpdig. I only uncompressed phpdig-1.8.0.zip to /usr/local/phpdig.
Thanks for your continued and quick support...