Add-Ins Ribbon Excel 2010 Worksheets

[AlbertoZap]

I made a Excel 2003 with macros and Add-Ins, .....Menus etc.
Now I create a Ribbon tab in Excel 2010.
when I put the tab Add-ins and click on the tab do not show the worksheet that supposed to be showed and do not show the UserForm
this is the code for Ribbon to call the Userform Precios

Option Explicit
Sub USERPRECIOS(ByVal CONTROL As IRibbonControl)
On Error Resume Next


Worksheets("Matriz").Activate


If Worksheets("Matriz").UsedRange.Rows.Count > 1 Then
Sheets("Matriz").Select
End If
Sheets("Matriz").Select


Precios.Show
End Sub

every thing is fine but when I click on the Tab do not do anything (no show Userform neither the sheet Matriz

does some body could help me with this code,
thank you in advanced
Alberto