Strange Graphics Error

ok... it's a very simple program.
AppTitle "Romules and Remus"
music = PlayMusic ("Eagleland__Onett.mid")
Graphics 611,349
SetBuffer BackBuffer ()
.start
intro = LoadImage ("tiberintro.bmp")
DrawImage intro, 0,0
Flip
begin$ = Input ("")
If begin$ = "" Then Goto slide1
.slide1
StopChannel music
music2 = PlayMusic ("sadness.mid")
Cls
Graphics 827,682
slde1 = LoadImage ("tiberbank.bmp")
DrawImage slde1, 0,0
Flip
WaitKey
Goto slide2
.slide2
StopChannel music2
music4 = PlayMusic ("notlike.mid")
Cls
Graphics 518,456
disagree = LoadImage ("disagree.bmp")
DrawImage disagree, 0,0
Flip
WaitKey
Goto slide3
.slide3
StopChannel music2
music3 = PlayMusic ("linktheme.mid")
Cls
Graphics 708,419
mount = LoadImage ("decide.bmp")
DrawImage mount, 0,0
Flip
WaitKey
Goto slide4
.slide4
StopChannel music3
music4 = PlayMusic ("fighting.mid")
Cls
Graphics 773,576
fight = LoadImage ("twinfight.bmp")
DrawImage fight, 0,0
Flip
WaitKey
Goto endshow
.endshow
StopChannel music4
endmusic = PlayMusic ("endmusic.mid.")
Cls
Graphics 522,403
endimg = LoadImage ("ending.bmp")
DrawImage endimg, 0,0
Flip
WaitKey
End