i think you have changed the name of certain npc inside the script.....
if you want to change the npc name ...make sure you change every single name of that npc that appear inside the script
https://rathena.svn.sourceforge.net/svnroot/rathena/trunk/src/config/renewal.h
/// renewal exp rate algorithms
/// (disable by commenting the line)
///
/// leave this line to enable renewal item exp rate algorithms
/// while enabled a special modified based on the difference between the player and monster level is applied
#define RENEWAL_EXP
comment this line if you dont want the renewal exp
you can try use the gettime() command to save the date data.
and use npc to check for the date data before give the reward.
and save it in a Permanent Character Data type or Account
if i was right..you are using the guild_vs map right ?
remove the GVG Mapflag
https://rathena.svn.sourceforge.net/svnroot/rathena/trunk/conf/mapflag/gvg.txt
// GvG Arenas =============
guild_vs1 mapflag gvg
guild_vs2 mapflag gvg
guild_vs3 mapflag gvg
guild_vs4 mapflag gvg
guild_vs5 mapflag gvg
remove it.