Hmm.... let me try, how about a code like this... Sorry, you got to have to search around if you're not familiar with the structure kind of lazy opening WE....
Event
Time Every 1 second //set the time to whatever you like depending on how fast you want the heroes to accumulate XP
Condition
None
Action
Set Temp_Group all units in the map matching unit type = hero
Pick all units in Temp_Group
Hero - add experience
call DestroyGroup( udg_Temp_Group )
EDIT:
hha I thought you were pertaining to the part where hero gets XP every interval..
Bogrim's right... Just set it at the gameplay constants....
Ghan has said he has fixed this. Monovertex please confirm this fix. This was only a problem with people that had signatures in the upper levels like not the special members but the respected members.