name() doesn't exists, use __unicode__ instead

coin/billing/admin.py

@@ -189,7 +189,7 @@ class InvoiceAdmin(admin.ModelAdmin):
 
 class PaymentAdmin(admin.ModelAdmin):
 
-    list_display = ('name', 'member', 'payment_mean', 'amount', 'date',
+    list_display = ('__unicode__', 'member', 'payment_mean', 'amount', 'date',
                     'invoice', 'amount_already_allocated', 'label')
     list_display_links = ()
     fields = (('member'),