Call stack error....

ID:146646
 
Apr 1 2005, 8:05 am
Code:
    Meditate()
        set category="Train"
        if(usr.meditating == 1)
            usr.icon_state = "[race]"
            usr << "<font size='1' color='green'><i>You stop meditating.</i></font>"
            usr.meditating = 0
        else
            usr.icon_state = "[race]_meditating"
            usr << "<font size='1' color='green'><i>You start meditating.</i></font>"
            spawn(30)
                usr.exp += 1
                usr.str += 1
                usr.dex += 2
                usr.pl += 1
                usr.energy -= 2
            usr.meditating = 1


Problem description:
You start meditating.
runtime error: type mismatch
proc name: Meditate (/mob/player/verb/Meditate)
source file: verbs.dm,158
usr: Joeyyy (/mob)
src: Joeyyy (/mob)
call stack:
Joeyyy (/mob): Meditate()

line 158 is the usr.exp += 1 line. I don't know what's wrong. I tried src.exp instead of usr.exp and that didnt work. I also tried exp by itself and that didnt work either. Someone help please!
Apr 1 2005, 8:15 am
For some reason, exp isn't a number. You put a string "2", or something else into it, so BYOND can't add a number to it.