The new getXP fonction you gave me, works pretty well. And I added this to my setskills function:
local gamestate = tonumber( et.trap_Cvar_Get('gamestate') )
if gamestate == 0 then
et.G_AddSkillPoints(playerID, 0, 500)
et.G_AddSkillPoints(playerID, 1, 500)
et.G_AddSkillPoints(playerID, 2, 500)
et.G_AddSkillPoints(playerID, 3, 500)
et.G_AddSkillPoints(playerID, 4, 500)
et.G_AddSkillPoints(playerID, 5, 500)
et.G_AddSkillPoints(playerID, 6, 500)
et.G_AddSkillPoints(playerID, 1, 500)
And the good gamestate number was 0, because 1 is for warmup and 0 is for when the game is started. Thanks a lot, my problem is fixed !