Always frustrating with only ftp access. Here are a couple of things you can try.

1. Add $! to end of your die's to see if error message gives you any clues.
2. send a test mail using pipe to Mail or mail this will verify to a certain extent if local accounts can send mail from that host plus headers may give a clue as to what MTA is being used.
3. Try looking for sendmail in /usr/sbin which is becoming more popular OR try opening sendmail without an absolute path, a long shot but worth a try.
4. several other places I have seen sendmail reside:
   1. /usr/bin, /etc, /var/lib
   2. /usr/local/bin ./etc ./sbin ./lib
5. you try shell script which -a sendmail > sendmailplace.

Hope this helps.

mitd-Made in the Dark
'My favourite colour appears to be grey.'