[Brian]

Here are the things I can remember which we know that can cause problems:

1) The mail that's being processed has to be plain text; processing HTML or rich text email would require much, much more complicated AppleScripts, which is how we're doing the processing.

2) Make sure that what appears in OmniFocus' "look for these characters in the subject of the email" field of preferences matches exactly what appears in the mail. Examples: if "-- " has been entered in preferences, and your email starts with "--something", your mail won't make it to OmniFocus because of the missing space character after the dashes.