Using sendmail for HTML body and binary attachment

Changing the Content transfer encoding type within the email from base64 to uuencode resolved the issue. Thanks for the inputs so far.

Given below is the revised script that works.

#!/usr/bin/ksh

export MAILFROM="[email protected]"
export MAILTO="[email protected]"
export SUBJECT="Test PDF for Email"
export BODY="email_body.htm"
export ATTACH="file.pdf"
export MAILPART=`uuidgen` ## Generates Unique ID
export MAILPART_BODY=`uuidgen` ## Generates Unique ID

(
 echo "From: $MAILFROM"
 echo "To: $MAILTO"
 echo "Subject: $SUBJECT"
 echo "MIME-Version: 1.0"
 echo "Content-Type: multipart/mixed; boundary=\"$MAILPART\""
 echo ""
 echo "--$MAILPART"
 echo "Content-Type: multipart/alternative; boundary=\"$MAILPART_BODY\""
 echo ""
 echo "--$MAILPART_BODY"
 echo "Content-Type: text/plain; charset=ISO-8859-1"
 echo "You need to enable HTML option for email"
 echo "--$MAILPART_BODY"
 echo "Content-Type: text/html; charset=ISO-8859-1"
 echo "Content-Disposition: inline"
 cat $BODY
 echo "--$MAILPART_BODY--"

 echo "--$MAILPART"
 echo 'Content-Type: application/pdf; name="'$(basename $ATTACH)'"'
 echo "Content-Transfer-Encoding: uuencode"
 echo 'Content-Disposition: attachment; filename="'$(basename $ATTACH)'"'
 echo ""
 #uuencode -m $ATTACH $(basename $ATTACH)
 uuencode $ATTACH $(basename $ATTACH)
 echo "--$MAILPART--"
) > email_`date '+%Y%m%d_%H%M%S'`.out
| /usr/sbin/sendmail $MAILTO