updatepanel usercontrol in popup+button click event not firing

actually i have to open a pop up window inside an update panel. and my popup content will come from user control. when i click on 'show popup' button, my pop is open but when i fill all contents and submit the form , the click event doesn't fired. my submit button is in the same user control...

i put my updatepanel-code which is in my PetUserControl....

<asp:UpdatePanel ID="upnlMain" runat="server" UpdateMode="Conditional">
<contenttemplate>

<asp:Label ID="lblMsg" runat="server">
<br />

<asp:HiddenField ID="hdnID" runat="server" />
<table class="valignmiddle">
<tbody>
<tr>
<td class="label-cell">
<label>Pet Name*</label></td>
<td>
<asp:TextBox ID="txtPetName" runat="server">

</td>
<td class="label-cell"></td>
<td class="label-cell">
<label>Owner</label></td>
<td>
<asp:DropDownList ID="ddlOwner" runat="server">
</td>
</tr>

<tr>
<td class="label-cell">
<label>Type of Pet</label>
</td>
<td>
<asp:DropDownList ID="ddlPetType" runat="server">
</td>
<td class="label-cell"></td>
<td class="label-cell">
<label>Breed</label>
</td>
<td>
<asp:DropDownList ID="ddlBreed" runat="server">
</td>
</tr>
<tr>
<td class="label-cell">
<label>Weight*</label></td>
<td>
<asp:TextBox ID="txtWeight" runat="server">


</td>
<td class="label-cell"></td>
<td class="label-cell">
<label>Age*</label></td>
<td>
<asp:TextBox ID="txtdob" runat="server">

</td>
</tr>
<tr>
<td class="label-cell">
<label>Gender</label></td>
<td>
<asp:DropDownList ID="ddlGender" runat="server">

</td>
<td class="label-cell">
<td class="label-cell">
<label>Active</label></td>
<td>
<asp:CheckBox ID="chkActive" runat="server">
</td>
</tr>
</tbody>

</table>
<br />

<table class="valignmiddle">
<tbody>
<tr>
<td class="label-cell">
<label>Is your pet allergic to any medications?</label></td>
<td>

<asp:RadioButtonList ID="rdIsYourPetAllergic" runat="server" AutoPostBack="true" OnSelectedIndexChanged="rdIsYourPetAllergic_SelectedIndexChanged">
<asp:ListItem>No
<asp:ListItem>Yes

</td>
</tr>

</tbody>
</table>
<br />

<table class="valignmiddle" id="PetAllergic" runat="server">
<tbody>
<tr>
<td class="label-cell">
<label>Please Select All