Time interrupt problem

[chai98a]

I got problem with time interrupt not work ....

How have known rule of time interrupt function pls advise, due to we found probble after we add more code on interrut sub and program will not work after run, But can done complier with out error.

here sample working :Portb.5 will flash after run.

OPTION_REG = $57 '57 Set TMR0 configuration
INTCON = $A0 ' Enable TMR0 interrupts

ON INTERRUPT GOTO INT

Main:
TMR0 = 0
Gosub check_Lstatus
Strobe = 1'strobe off
latch = 1'lactch off
clock = 1'CLOCK OFF ACTIVE HIGH
Sin3 = 0
Sin2 = 0
SIN1 = 0
goto loop
...
....
...
disable
INT:
INTCON.2 = 0
TMR0 = 0
'HSEROUT ["n1 ",dec n,13,10]
TOGGLE PORTB.5

resume
enable

But not work if we add some more code below to replace or below " toggle portb.5"

=======

disable
INT:
INTCON.2 = 0
TMR0 = 0
'HSEROUT ["n1 ",dec n,13,10]
TOGGLE PORTB.5
FOR K = 0 TO 2
READ (FONT1+K),COLUM2
READ (FONT2+K),COLUM0
READ (SCANROW0+K),ROW0

GOSUB SCANDATASIN8BITLOWBYTE

READ (FONT0+K),COLUM3
READ (FONT1+K),COLUM1
READ (SCANROW1+K),ROW1

GOSUB SCANDATASIN8BITHIGHBYTE

LATCH = 0
LATCH = 1
STROBE = 0
STROBE = 1

next k

FOR K = 8 TO 10
READ (FONT1+K),COLUM2
READ (FONT2+K),COLUM0
READ (SCANROW0+K),ROW0

GOSUB SCANDATASIN8BITLOWBYTE

READ (FONT0+K),COLUM3
READ (FONT1+K),COLUM1
READ (SCANROW1+K),ROW1

GOSUB SCANDATASIN8BITHIGHBYTE

LATCH = 0
LATCH = 1
STROBE = 0
STROBE = 1

NEXT K
resume
enable
============


Who have pls advise too .. thank you

Pls see full code on attached file.