Xxxxxxxxxxlog is incorrect for a "configuration patch"; what you paste into the Subject line and into the body of the email should be a 10 digit number only. To that email message, you attach the patch file, which has a .ptc extension.
More detailed instructions on patch files can be found here:
http://forum.nrgsystems.com/forums/t/10.aspx
When you do a "sensor patch", the patch file will have a format of xxxxxxxxxxlog.ptc; however, what you past into the Subject line and into the body of the email should only be a 10 digit number (no "log" and without a file extension).