Editting drops in NextGen 3.9

Hey guys, first post here, expect general noobness, I'm new.
Anyway, I'm trying to create a NextGen 3.9 server to play with my friends locally, managed to get it up after some fiddling and now I'm encountering issues with customising the drop rates.
So, editted some values in the npc_drops under static data (I don't think I'm meant to change it there), which gives me what feels like an unfixable error when running the GameServer:

Code:

---

==========================[ ##### STATIC DATA ##### ]==========================
23:49:12.902 ERROR[main]: - Error while merging xml files
javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1,1]
Message: Content is not allowed in prolog.
        at com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.next(XMLS
treamReaderImpl.java:598) ~[na:1.7.0_45]
        at com.sun.xml.internal.stream.XMLEventReaderImpl.nextEvent(XMLEventRead
erImpl.java:83) ~[na:1.7.0_45]
        at com.aionemu.gameserver.dataholders.loadingutils.XmlMerger.importFile(
XmlMerger.java:399) ~[NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.loadingutils.XmlMerger.processImpo
rtElement(XmlMerger.java:330) ~[NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.loadingutils.XmlMerger.doUpdate(Xm
lMerger.java:252) ~[NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.loadingutils.XmlMerger.process(Xml
Merger.java:181) ~[NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.loadingutils.XmlDataLoader.mergeXm
lFiles(XmlDataLoader.java:132) [NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.loadingutils.XmlDataLoader.loadSta
ticData(XmlDataLoader.java:71) [NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.DataManager.<init>(DataManager.jav
a:200) [NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.DataManager.<init>(DataManager.jav
a:36) [NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.DataManager$SingletonHolder.<clini
t>(DataManager.java:286) [NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.DataManager.getInstance(DataManage
r.java:191) [NG-Game.jar:na]
        at com.aionemu.gameserver.GameServer.main(GameServer.java:221) [NG-Game.
jar:na]
23:49:12.903 ERROR[main]: - Critical Error - Thread: main terminated abnormaly:
java.lang.Error: Error while merging xml files
java.lang.Error: Error while merging xml files
        at com.aionemu.gameserver.dataholders.loadingutils.XmlDataLoader.mergeXm
lFiles(XmlDataLoader.java:136) ~[NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.loadingutils.XmlDataLoader.loadSta
ticData(XmlDataLoader.java:71) ~[NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.DataManager.<init>(DataManager.jav
a:200) ~[NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.DataManager.<init>(DataManager.jav
a:36) ~[NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.DataManager$SingletonHolder.<clini
t>(DataManager.java:286) ~[NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.DataManager.getInstance(DataManage
r.java:191) ~[NG-Game.jar:na]
        at com.aionemu.gameserver.GameServer.main(GameServer.java:221) ~[NG-Game
.jar:na]
Caused by: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1,1]
Message: Content is not allowed in prolog.
        at com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.next(XMLS
treamReaderImpl.java:598) ~[na:1.7.0_45]
        at com.sun.xml.internal.stream.XMLEventReaderImpl.nextEvent(XMLEventRead
erImpl.java:83) ~[na:1.7.0_45]
        at com.aionemu.gameserver.dataholders.loadingutils.XmlMerger.importFile(
XmlMerger.java:399) ~[NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.loadingutils.XmlMerger.processImpo
rtElement(XmlMerger.java:330) ~[NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.loadingutils.XmlMerger.doUpdate(Xm
lMerger.java:252) ~[NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.loadingutils.XmlMerger.process(Xml
Merger.java:181) ~[NG-Game.jar:na]
        at com.aionemu.gameserver.dataholders.loadingutils.XmlDataLoader.mergeXm
lFiles(XmlDataLoader.java:132) ~[NG-Game.jar:na]
        ... 6 common frames omitted

---

If I restore the old npc_drops.xml then this error goes away.

PS. I've tried changed my language to English (from English), and it doesn't help.

Also, the AionDropEditor that's available for AL isn't applicable for NextGen because there doesn't seem to be any .dat file to open. So, could anyone help me out by telling me how I go about editting drops in Aion NextGen 3.9, or how to work around the error above.

Thanks in advance!