Hello,
I use Windows7, and play through Time Warner Internet on a CATV connection, unsure how fast but it's very fast.

On 1/13 at 11:24pm PST I tried to trade the items necessary to upgrade Summoners Artifact armor 109 feet into 119. This was through the NPC Monisette in Port Jueno. The NPC did not react, did not take the items, etc.

I tried:
1) putting the 109 piece in storage and then taking it out and trying again
2) zoning and retrying
3) clicked the npc and read the items required for the 119 upgrade to ensure I was trading the right things (I was)
4) re-arranging the order of items in the trade boxes
5) tried different upgrade (which was accepted) and then retried this after I got the item back

Nothing worked, I tried many times. The NPC did not do a thing. I gave up and traded the summoner 109 legs & items to upgrade to 119, and the NPC accepted it.

This was on the Fenrir server, character name Gukai, Elvaan M. I was geared as a 99 black mage, solo.