How to deal with undefined variable

I have a classic ASP page. On the page I have table cells that were setup to work like buttons (see code below). If a certain variable is not populated I want to display disabled cells. Here is what I have but when the page is first loaded I get an error that the variable is not defined. How do I deal with this?

Code:

---

            <%
            If(Request("dspLayoutName") != "")
            {
            %>
            <td onmouseover = "this.className='toolbaron';" visible= "true" onmouseout = "this.className='toolbaroff';" nowrap class="toolbaroff" onclick="onSubmit();">Save Layout</td>
            <td onmouseover = "this.className='toolbaron';" visible= "true" onmouseout = "this.className='toolbaroff';" nowrap class="toolbaroff" onclick="onSaveAs();">Save Layout AS...</td>             
            <td onmouseover = "this.className='toolbaron';" visible= "true" onmouseout = "this.className='toolbaroff';" nowrap class="toolbaroff" onclick="onCloneFloorObjects();">Clone Layout</td>             
            <%
            }
            else
            {
            %>
            <td nowrap class="toolbaroff">Save Layout</td>
            <td nowrap class="toolbaroff">Save Layout AS...</td>             
            <td nowrap class="toolbaroff">Clone Layout</td>             
            <%
            }
            %>

---

Thanks for your help.