how to make fortran random number

i wanna make rand number without using functions

PROGRAM RTEST
  PARAMETER (N=100)
  IMPLICIT REAL(A-H,O-Z), INTEGER(I-N)
  DIMENSION A(N)
  OPEN(99,FILE='RANDOM.DAT',FORM='FORMATTED')
  IBMO=3149
  SUM=0.0
  DO 5 I=1,N
  IBMO=IBMO*65549
  IF(IBMO) 101, 102, 102
  101 IBMO=IBMO+2147483647+1
  102 RANDOM=0.46566128E-9*IBMO
  A(I)=RANDOM
  WRITE(99,10)I,A(I)
  WRITE(6,10) I,A(I)
   10 FORMAT(5X,I4,3X,F12.7)
  SUM=SUM+A(I)
  AVE1=SUM/FLOAT(N)
   20 FORMAT(12X,F12.7)
   30 FORMAT(5X,I4,3X,F12.7)
  WRITE(6,20) AVE1
  WRITE(99,30)I,AVE1
    5 CONTINUE
  CLOSE(99)
  AVE=SUM/FLOAT(N)
  WRITE(6,*)AVE
  PAUSE
  STOP
  END

but i always got integer overflow or invalid floating point error.....

so what my think was type error

i try to change real >> real*8 and integer >> integer*8

but every try was fail....

what is problem?