Label for checkbox input type

I have two cases. Case 1:

    <div class="form-group form-group-terms">
                                    <div class="checkbox ch-terms">
                                        <s:if test="%{givingDetailsDispBean.isTermsCondChecked}" >
                                            <input type="checkbox" value = "3" name="TnCCheckbox" id="TnCCheckbox" checked="checked" class="radio" <s:if test="%{#addToCartdisabled}"> disabled = "disabled"</s:if>>
                                        </s:if>
                                        <s:else>
                                            <input type="checkbox" value = "3"id="TnCCheckbox" name="TnCCheckbox"  class="radio" <s:if test="%{#addToCartdisabled}"> disabled = "disabled"</s:if>>
                                        </s:else>
                                        <label for="TnCCheckbox">
                                            <label:text name="rex.label.excessbaggage.tnc"/>
                                        </label>
                                    </div>
                                </div>

In This case my checkbox works fine.But A-checker shows error and ask me to put label on inputs

Case 2:

<div class="checkbox ch-terms">
                                        <s:if test="%{givingDetailsDispBean.isTermsCondChecked}" >
                                            <label for="TnCCheckbox">
                                            <label:text name="rex.label.excessbaggage.tnc"/>
                                            </label>
                                            <input type="checkbox" value = "3" name="TnCCheckbox" id="TnCCheckbox" checked="checked" class="radio" <s:if test="%{#addToCartdisabled}"> disabled = "disabled"</s:if>>
                                        </s:if>
                                        <s:else>
                                            <label for="TnCCheckbox">
                                            <label:text name="rex.label.excessbaggage.tnc"/>
                                            </label>
                                            <input type="checkbox" value = "3"id="TnCCheckbox" name="TnCCheckbox"  class="radio" <s:if test="%{#addToCartdisabled}"> disabled = "disabled"</s:if>>
                                        </s:else>

                                    </div>

In this case my checkbox does not work and A-checker does not show the error. I do not understand why this happens. I am using A-cheker to validate my website.