too many values with string.split

[Shawn Minisall]

I'm trying to unpack a list of 5 floats from a list read from a file and 
python is telling me 5 variables are too many for the string.split 
statement.  Anyone have any other idea's?  NOTE: the only reason I 
convert it to a float instead of just leaving it as a string in the loop 
is because I have to have it printed out as a float besides the names 
and then the average displayed underneath

thx

    #read in data line by line
    for line in infile:
        mylist = string.split(line)
        firstName[counter] = mylist[0]
        lastName[counter] = mylist[1]
        grades[counter] = float(mylist[2])
        print firstName[counter], 
lastName[counter],":","\t\t",grades[counter]
        #increment counter
        counter = counter + 1

    #calculates and prints average score
    grades = str(grades)
    num1, num2, num3, num4, num5 = string.split(grades,",")
    average = float(num1 + num2 + num3 + num4 + num5) / 5
    print
    print "Average:"