This is my  'poor-man-solution' about that problem. I found that problem last night, maybe a bug in skin management? I don't know.
I have to dig a little more to understand why that happens...

The solution involves to modify the skin container to include a print icon. By example, if you are using the DNN - Blue skin you have to modify the Image Header - Color Background.ascx  in Portal\_default\Containers\DNN - Blue or the skin container thar you are using:

<%@ Register TagPrefix="dnn" TagName="PRINTMODULE" Src="~/Admin/Containers/PrintModule.ascx" %>

and include a reference in the container, by example:
......
            <TABLE width="100%" border="0" cellpadding="0" cellspacing="0">
              <TR>
                <TD align="left" valign="middle" nowrap><dnn:ACTIONBUTTON1 runat="server" id="dnnACTIONBUTTON1" CommandName="AddContent.Action" DisplayIcon="True" DisplayLink="True" /></TD>
                <TD align="right" valign="middle" nowrap><dnn:ACTIONBUTTON2 runat="server" id="dnnACTIONBUTTON2" CommandName="SyndicateModule.Action" DisplayIcon="True" DisplayLink="False" />&nbsp;<dnn:ACTIONBUTTON3 runat="server" id="dnnACTIONBUTTON3" CommandName="PrintModule.Action" DisplayIcon="True" DisplayLink="False" />&nbsp;<dnn:ACTIONBUTTON4 runat="server" id="dnnACTIONBUTTON4" CommandName="ModuleSettings.Action" DisplayIcon="True" DisplayLink="False" /></TD>

              </TR>
  <TR><td><dnn:PRINTMODULE runat ="server" id="dnnPrintModule"/></td>
            </TABLE>
.....
Obviously, this workaround has serious drawbacks, like the print button figures in ALL modules...

Is anyone with better ideas?

Thanks...  I'm going to try and put it in the edit frame itself instead of the skin and see if that works...  That should prevent it from appearing in all modules...  Unless someone comes up with a better idea...