Nice improvement, thanks for sharing.
But I think the change in exp.cpp isnt correct. Like in the AddExp() line, you need to refer either to tmp oder tmp2, so...
Code:
cmember->Message(15,"Your share of the Group XP is %u", (tmp < tmp2 ? tmp : tmp2) ); //Shows the amount of group XP gained (RDurbin)
EDIT: Maybe it would make more sense to show the group xp share in percent, cause you wont get the amount that is displayed. AddEXP() will change it depending on the mobs conlevel.