can't save combobox

[topsykretts]

I'm so newbie. Badly need ur help. on a form i put a combobox retrieved from a different table. it works fine. but when i filled in all the entries and saved them, it didn't save. still empty. before is used the combo, it was just fine.
here's the script ( a little), for a start. btw, it's vb6.

Private Sub Form_load()
Set wjt = CreateWorkspace("", "admin", "", dbUseJet)
Set a = wjt.OpenDatabase("D:\My Documents\VB_Practice\db1.mdb")
Set a = OpenDatabase("D:\My Documents\VB_Practice\db1.mdb")
Set b = a.OpenRecordset("student")
Set f = a.OpenRecordset("select distinct (class)  from rombel")

cboclass.Text = f!class
    
        With cboclass
        .Clear
   On Error Resume Next
   If f.RecordCount = 0 Then
   MsgBox "type in data", vbOKOnly
    
        Else
                  f.MoveFirst
        Do Until f.EOF
            .AddItem f(0)
        
            f.MoveNext
    
        Loop
       End If
       End With
 
   Return

    If b.RecordCount = 0 Then
Call empty
Else
b.MoveFirst
End If
change= False
End Sub

Here's the save script:

Private Sub save_Click()
b.AddNew
b!no = tno.Text
b!nisn = tnisn.Text
b!class = cboclass.Text
b!name = tname.Text
b!sex= tsex.Text
b.Update
Call empty
tno.SetFocus
End Sub

after clicking save, and click the next button, it show "no current record" [runtime error '3021']

i assumed it's bcoz of the combobox which is probably not properly set.
any idea? please.

tx b4