Trade Problem/Bug

[Pyrodrew]

I currently have my capital trade networked with Persia's capital. Neither Persia or I are in any wars. Persia has 3 Incenses at Istakhr connected with roads as displayed below (this is a recent territory map of Persia)... these roads are connected to Persia's capital, but do go thru a small part of Babylonian land. Babylonians are peaceful with both Persia & I although we were at war once. My trade network to reach the Istakhr Incense goes thru Persia than thru Babylonian land & finally reaches the Istakhr Incense. F4 screen shows Persia & I have "possible trade" available. Yet when I go to trade with Persia the Incense Resource is not shown as an option to trade AT ALL (not even a "Incense(0 extra)".

Why?

Someone mentioned Incense having more files than the other resources... is there a problem or bug with incense?

[Fleche]

AI probably already traded it off to another AI

[Pyrodrew]

If that were true I would see "Incense (0 extra)".

[Todd Hawks]

Are you sure you don't already have incense?

Check with the F2-Key.

Other possibility: The trade route is interrupted by going through enemy territory.