Syntax error in MIPS assembly

Question

I'm having a strange problem with an assembly file. Every time I load this file into PCSpim, it gives me a syntax error on line 23. I've looked at several references and asked several classmates for help, and nobody seems to understand what's wrong.

.globl main

.data
test1:     .word 92
test2:     .word 81
finalExam: .word 90
a:         .ascii "Enter value A:\n"
b:         .ascii "Enter value B:\n"
grade:     .word 0
result:    .word 0
#More data...

.text
#Program calculates a final grade based off of two midterms and a final. Midterms are
#weighted 30% and the final is weighted 40%. Grade is out of 1000.
final: 
li    $t4, 3 #PCSpim complains here.
li    $t5, 4
la    $t0, test1
lw    $t1, ($t0)
mult  $t1, $t4
mflo  $t1
la    $t0, test2
lw    $t2, ($t0)
mult  $t2, $t4
mflo  $t2
la    $t0, finalExam
lw    $t3, ($t0)
mult  $t3, $t5
mflo  $t3
add   $t4, $t1, $t2
add   $t4, $t4, $t3
la    $t0, grade
sw    $t4, ($t0)
#Print result to console
li    $v0, 1 
move  $a0, $t4
syscall
jr    $ra

#Program continues...

Answer 1

Okay, figured it out, there were two problems in this situation. First, Bare Machine should have been disabled, and another problem came up when I used "b" as a label, because b is also used as an opcode.

Thanks for checking this out!