My provider confirmed that the sendmail location is good, once I took out the vertical line (|) before /usr...then I was getting an error message saying "Cannot open sendmail: No such file or directory at upload.cgi line 64." So, they had me remove the -t key from the "/usr/sbin/sendmail" instruction, and then I stopped getting an error...but I still haven't gotten any email notification as a result of the test.
I know the email address I am using is good, and I have it listed as per your example above (print SENDMAIL "Send-to: you\@your.com\n";), with my good address instead of the generic addy, or course.
I Googled it and found a slightly different version of the script, that basically used just MAIL instead of SENDMAIL, but it also included a final line of:
print MAIL "\n.\n";
...before the "close( MAIL );" line, which the tutorial I found online said would tell sendmail to actually send the message, but I still received no email when I used those modifications. I've checked my junk mail folder online for the email account in the "send to" field, but still nothing.