Just curious if you ever resolved it?

If the price of the ticket you purchased is lower then say around 17000 yen, then yes you probably don't have everything you need.

If the price you paid is around 11340 you have the basefare and just need the limited express supplement, if the price you have is just around 6000~ then you just have the limited express supplement and need a basefare ticket.

Here's a photo from JR Central:
http://english.jr-central.co.jp/tickets/read/index.html