ok i got the orthros one and the one from the soldier then i went to guy who is in love and then i went back dalan and the guy who is lookin for the fragments he says i got 2 peice but i remember doing something wit da waterway controls and i got a peice to
From Split Infinity's Guide http://www.gamefaqs.com/console/ps2/file/459841/46240
Based on the info you've provided I think this is what you need:
1) Speak with Filo in the southeast corner of Lowtown. She mentions that her group has checked everywhere but the city streets.
2) Go to the Southern Plaza of Rabanastre and speak with the Curious Woman by the fountain. Listen to what she has to say. She will mention a necklace that was given to her, but she can't remember where she got it from.
3) Enter Muthru Bazaar and speak the Bangaa Merchant (labeled as "Merchant"). Ask about the necklace. He will tell you that he sold a necklace to an Imperial. The Imperial is supposedly hanging out at one of the shops around town.
4) Enter Yugri's Magicks. Speak with the Sotted Imperial kneeling to the left. Ask about the necklace. Tell him about the womand near the fountain.
5) The woman will not be near the fountain when you go back to Southern Plaza, so go back to the North Sprawl of Lowtown and talk to Kytes near Warehouse #5 (Garamsythe Waterway entrance). Hear both sets of news, doesn't matter which is first.
6) Speak with Filo again in the southeast corner of Lowtown. Tell her you need to see the woman. Agree to go with her and you will be taken straight to Yugri's Magicks.
7) Talk with the Sotted Imperial. A conversation will commence then the girl (Curious Woman) will hand over the ++GRIMY FRAGMENT++.
8) Give all three fragement pieces to Roh'kenmou back in Old Dalan's Place. He asks Vaan to visit Nabudis later.
9) Go to Archades and enter Charlotte's Magickery. Speak with Roh'kenmu at the top of the stairs. Inquire about the Moonsilver Medallion when he asks. It turns out that he sold the Moonsilver Medallion to a person named Otto.
10) Enter Old Archades and talk to Otto (Proper Gent) in the northeast portion of the Alley of Muted Sighs. After a brief conversation, Otto will hand over the ++MOONSILVER MEDALLION++.
11) Return to Charlotte's Magickery and hand over the Moonsilver Medallion to Roh'kenmu.
12) Return to the Nabreus Deadlands and speak with Ma'kleou once again at the top of the Muted Scarp.
All three of the Acolytes will now be grouped at the Muted Scarp. He will mention three beasts: Humbaba, Fury, and Chaos. He says that they were sealed away after a great battle. He mentions that the final medallion, the Medallion of Might rest in a small shrine in the Overlooking Eternity portion of the Nabreus Deadlands. They will then travel to the Overlooking Eternity and await your party's entry.
If this doesn't help check the guide above as there is more info there than you thought possible.
You must not only aim aright, but draw the bow with all your might. - Henry David Thoreau