error when checking

[MNDRBNDR]

Code:

SETUP:
CLS
SCREEN 12
SLEEP 240
DIM X AS INTEGER,Y AS INTEGER, BUTTONS AS INTEGER
DIM STATUS(200)
DIM SEQ(200)
CIRCLE (300,150),50,4
CIRCLE (200,250),50,2
CIRCLE (400,250),50,3
CIRCLE (300,350),50,7
LENGTHOFSEQUENCE=5
B$=""
A$=""

GAME:
GOSUB MAKESEQUENCE
LOCATE 25,25:PRINT A$
LOCATE 26,25:PRINT B$
SLEEP 500
DO
A$=INKEY$
IF A$=CHR$(255)+"X" THEN SYSTEM
IF A$=CHR$(27) THEN SYSTEM
GETMOUSE X,Y,,BUTTONS
IF X>249 AND X<351 AND Y>101 AND Y<201 AND BUTTONS=1 THEN  B$=B$+"T":GOSUB TOPLIGHT
IF X>149 AND X<251 AND Y>200 AND Y<302 AND BUTTONS=1 THEN  B$=B$+"L":GOSUB LEFTLIGHT
IF X>349 AND X<451 AND Y>200 AND Y<302 AND BUTTONS=1 THEN  B$=B$+"R":GOSUB RIGHTLIGHT
IF X>249 AND X<351 AND Y>298 AND Y<402 AND BUTTONS=1 THEN  B$=B$+"B":GOSUB BOTTOMLIGHT
IF A$=B$ THEN EXIT DO
LOOP
LOCATE 24,25:PRINT "EXITED"
SLEEP 500
LENGTHOFSEQUENCE=LENGTHOFSEQUENCE+1
A$=""
B$=""
GOTO GAME

LOSE:
LOCATE 25,25:PRINT "SORRY"
SLEEP 300
GOSUB GAME

MAKESEQUENCE:
FOR T=1 TO LENGTHOFSEQUENCE
SEQINT=INT(RND(1)*5)
IF SEQINT=1 THEN A$=A$+"T":GOSUB TOPLIGHT
IF SEQINT=2 THEN A$=A$+"B":GOSUB BOTTOMLIGHT
IF SEQINT=3 THEN A$=A$+"L":GOSUB LEFTLIGHT
IF SEQINT=4 THEN A$=A$+"R":GOSUB RIGHTLIGHT
IF SEQINT=5 THEN A$=A$+"T":GOSUB TOPLIGHT
NEXT T
RETURN

TOPLIGHT:
FOR R=49 TO 1 STEP-1
CIRCLE (300,150),R,4
NEXT R
SLEEP 160
FOR R=49 TO 1 STEP-1
CIRCLE(300,150),R,0
NEXT R
RETURN

BOTTOMLIGHT:
FOR R=49 TO 1 STEP-1
CIRCLE (300,350),R,7
NEXT R
SLEEP 160
FOR R=49 TO 1 STEP-1
CIRCLE(300,350),R,0
NEXT R
RETURN

LEFTLIGHT:
FOR R=49 TO 1 STEP-1
CIRCLE (200,250),R,2
NEXT R
SLEEP 160
FOR R=49 TO 1 STEP-1
CIRCLE(200,250),R,0
NEXT R
RETURN

RIGHTLIGHT:
FOR R=49 TO 1 STEP-1
CIRCLE (400,250),R,3
NEXT R
SLEEP 160
FOR R=49 TO 1 STEP-1
CIRCLE(400,250),R,0
NEXT R
RETURN