My past experience is:

Notes labeled “Pilot Note” sync.
All Custom Fields, Email 2, URL’s, etc. are appended to the Notes section on your Palm device.
Go back to a previous working backup of NUDC contact file and see if that helps.

FYI, Now Software is out of business. If you’re committed to a Treo 755 I wouldn’t worry about tracking down a copy of Now X. However, you may want to review Missing Sync for Palm.