Trouble w/ SIMPLEINVOICES web-based application for ISPCONFIG webs. (htaccess???)

I have a client that wants to run SimpleInvoices web-based invoicing application on his website. The program is simple to install... extract the .zip contents to a folder in the users "web" directory (i.e. web/simpleinvoices), edit the config.php file to point to the users database and ADD THE UNW for htaccess -- I assume this is the UNW from the users .htpasswd file (i.e. var/www/web8/.htpasswd)?. The application is then accessible via http://www.domain.com/simpleinvoices/ .

My problem is the application has a feature of exporting invoices to .pdf. Everything works EXCEPT when it outputs the .pdf for download, the .pdf is BLANK.

here is there errors from the web users log file (i.e. /var/www/web8/log/error.log); NOTE: users ip address and domain name have been edited.

I am not sure what that means exactly??? It looks as though the application is unable to connect to that url using the "http://htusername:[email protected]"

If I type the URL in WITHOUT the htusername:[email protected] like this: http://users.domain.com/simpleinvoi...s/template&invoice=8&action=view&location=pdf I get the proper output...

Thanks for any help!