http://www.playonline.com/pcd/topics/ff11us/detail/6599/detail.html

It says:

In keeping with the Vana'versary tradition, distinguished individuals from across the realm have sent congratulatory letters to the moogles. In addition to conveying these thankful tidings, moogles are also floating at-the-ready to deliver some elegant formalwear to any adventurer who asks. Converse with a moogle at one of the locations below to claim yours! Once you have donned your new garb, speak with the purple-winged vendor again for an opportunity to prove your gallantry to all mooglekind.

*Moogles will be doling out Dinner Jackets and Dinner Hose this year as well. Adventurers who missed out on these items in the past may examine the box beside the moogle that reads, "Free to take."

following locations:
Southern San d'Oria (I-8) / Bastok Markets (F-8) / Windurst Waters (north side) (F-9)
It seems to me like a part of the text is missing there. Please check this.