[RESOLVED] Extension gone

[eject]

Hello..i have a problem when creating a file with extension in one of computer that use my system. The extension gone when the system create the file.

I used below code to create a scan.dat file. please ignore other (not related) code. But the problem is when the system create the file, it become 'scan' (without extension). This problem only happen in one pc. other pc run the code well and produce scan.dat.
Can somebody solve for me? i cannot see the problem.
Thanks..

Sub Output_ScanDat()
Dim loc As String

Open App.Path & "\scan.dat" For Append As #1

ap$ = Chr$(34)
bt$ = ap$ + "," + ap$
a$ = ap$ + "A000001" + bt$
b$ = Mid$(Date$, 1, 2) + Mid$(Date$, 4, 2) + Mid$(Date$, 9, 2) + bt$
h$ = Mid$(Time$, 1, 2) + Mid$(Time$, 4, 2) + Mid$(Time$, 7, 2) + bt$
b$ = a$ + b$ + h$


g$ = bt$ + Trim(Form1.txtLoc.Text) + ap$

For I = 1 To nldiff
c$ = b$ + Trim(quantity(I)) + bt$ + parts(I) + bt$ + lots(I) + bt$ + "A000000" + bt$
Pref2$ = Mid$(lots(I), 1, 2)
Pref1$ = Mid$(lots(I), 2, 1)

loc = GetLocationByLot(Pref2$)
If loc = "FG??" Then

invloc = 1
Else
invloc = 0
End If



f$ = c$ + loc + g$
Print #1, f$
Next I
Close 1

End Sub