vb调用fortran的dll

Fortran源程序：
SUBROUTINE ARRAYTEST (n, arr)
! $ ATTRIBUTES DLLEXPORT :: ARRAYTEST
INTEGER n, i, j
REAL (4) arr (3, 3)
DO i= 1, 3
DO j= 1, 3
arr ( i, j) = 10.1*i+j
END DO
END DO
n= n+ 10
END SUBROUTINE
VB源程序（一个窗体，两个文本框，一个命令控件）：
模块里为：Private Declare Sub ARRAYTEST Lib "C:\xinjian\exam\Debug\exam.dll" Alias "_ARRAYTEST@8" (X As Long, Y As Single)

Private Sub Command1_Click()
Dim a As Long
Dim ab(1 To 3, 1 To 3) As Single
a = 10
Call ARRAYTEST(a, ab(1, 1))
Text1.Text = Str(a)
Text2.Text = Str(ab(3, 3))
End Sub
运行显示函数未定义，应该怎么解决呀？求助！