Email attachment also sends .dat file

I have a page that sends out an email with a number of attachments. I have 2 static attachments with the file urls pulled in from database fields. These fields are not always filled in and so there wont always be an attachment sent out with the email. I also have a repeat region attachment that can send none, 1 or multiple attachments. Everything works fine - the email sends out as do the attachments whether there be none, 1 or multiple.

The problem is that along with the attachment the email sends .dat files and the name of these .dat files is the same name as the folder (clientconf.dat) in which the attachments are stored on my server.

Here is the bit of code from the email file

//Attachment Entries
$WA_MailObject = WAUE_AddAttachment($WA_MailObject,"clientconf/".($Payments->getColumnVal("ATOLCert")) ."");
do {
$WA_MailObject = WAUE_AddAttachment($WA_MailObject,"clientconf/".$row_service["UploadConf"] ."");
} while ($row_service = mysql_fetch_assoc($service));
$WA_MailObject = WAUE_AddAttachment($WA_MailObject,"clientconf/".($ServiceFlight->getColumnVal("UploadConf")) ."");

This isn't too much of a problem however I have had quite a few clients contacting me to say they can't open all the attachments and can I resend them.