Another code inspection.

Meade.net/Properties/Resources.Designer.cs

@@ -135,5 +135,14 @@ namespace ASCOM.Meade.net.Properties {
                 return ResourceManager.GetString("SetupDialogForm_TextBox1_TextChanged___0_00_0___of_sidereal_rate_", resourceCulture);
             }
         }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Please enter only numbers..
+        /// </summary>
+        internal static string SetupDialogForm_txtElevation_TextChanged_1_Please_enter_only_numbers_ {
+            get {
+                return ResourceManager.GetString("SetupDialogForm_txtElevation_TextChanged_1_Please_enter_only_numbers_", resourceCulture);
+            }
+        }
     }
 }

Meade.net/Properties/Resources.resx

@@ -144,4 +144,7 @@ Valid are : -register, -unregister and -embedding</value>
   <data name="SetupDialogForm_SetupDialogForm__0__Settings___1__" xml:space="preserve">
     <value>{0} Settings ({1})</value>
   </data>
+  <data name="SetupDialogForm_txtElevation_TextChanged_1_Please_enter_only_numbers_" xml:space="preserve">
+    <value>Please enter only numbers.</value>
+  </data>
 </root>

Meade.net/SetupDialogForm.cs

@@ -169,7 +169,7 @@ namespace ASCOM.Meade.net
         {
             if (System.Text.RegularExpressions.Regex.IsMatch(txtElevation.Text, "[^0-9]"))
             {
-                MessageBox.Show("Please enter only numbers.");
+                MessageBox.Show(Resources.SetupDialogForm_txtElevation_TextChanged_1_Please_enter_only_numbers_);
                 txtElevation.Text = txtElevation.Text.Remove(txtElevation.Text.Length - 1);
             }
         }
@@ -178,7 +178,7 @@ namespace ASCOM.Meade.net
         {
             if (System.Text.RegularExpressions.Regex.IsMatch(txtBacklashSteps.Text, "[^0-9]"))
             {
-                MessageBox.Show("Please enter only numbers.");
+                MessageBox.Show(Resources.SetupDialogForm_txtElevation_TextChanged_1_Please_enter_only_numbers_);
                 txtBacklashSteps.Text = txtElevation.Text.Remove(txtBacklashSteps.Text.Length - 1);
             }
         }