AjaxCalendar extender not showing Saturday in Chrome, Firefox or Safari

Having a bit of trouble with CalendarExtender here in the project. Basically it doesn't show Saturdays in Chrome, Firefox or Safari, but it does show them fine in IE. Obviously this is a bit of a problem.

I've tried stuffing with CSS to no avail and that's why I come here for help! Saturday is there, but they don't show how this painting is (due to my novelty, I'm not allowed to send images directly!):

http://i.neoseeker.com/mgv/385085/85/87/calendarerror_display.png

Hope you can do this in the picture, but actually I have a selected Saturday confirmed by a popup, but it's useless as it is.

Here is the code, hopefully it can give some idea of ​​what I am doing wrong D:

<div id="left">
<h1>FIND EVENT</h1>
<br />
<asp:TextBox ID="txtFind" runat="server" AutoPostBack="True" CssClass="txt" OnTextChanged="txtFind_TextChanged" Width="175px" ForeColor="#999999">Click to Find Date</asp:TextBox>  
<asp:CalendarExtender ID="calFindDate" runat="server" TargetControlID="txtFind" Format="dd/MM/yyyy"></asp:CalendarExtender> 
<br />
<asp:ListBox ID="lstbxFind" runat="server" AutoPostBack="True" Height="390px"     Width="182px" OnSelectedIndexChanged="lstbxFind_SelectedIndexChanged"></asp:ListBox>
<br />
<asp:LinkButton ID="lnkbtnNew" runat="server" CssClass="lnk" OnClick="lnkbtnNew_Click">New</asp:LinkButton>
<asp:LinkButton ID="lnkbtnDelete" runat="server" CssClass="lnk" OnClientClick="return confirm('Are you sure you want to delete this fixture event?')"                              onclick="lnkbtnDelete_Click">Delete</asp:LinkButton>
 <div id="email" runat="server" class="confirm">Event Saved</div>
 <asp:LinkButton ID="lnkbtnSave" runat="server" CssClass="lnk" OnClick="lnkbtnSave_Click" ValidationGroup="Group1">Save</asp:LinkButton>
 <br />  
 <br />
 <!-- <br />       
 <asp:Label ID="Label1" runat="server" ForeColor="#F6F6F6" Text="Label"></asp:Label>-->
 </div>

      

        
        
        
      

    

Hopefully this makes sense to someone and can at least point me in the right direction. I'm new to C # and whatnot, so I'm certainly looking into working here! Thank.