channel form not working on index

Question

this is my form:

{exp:channel:form channel="contactform" return="contact/dank" include_jquery="no"  include_assets="no"}
<div class="span6">
    <div class="field mandatory">
            <input type="text" class="text-input mandatory" size="33"  name="firstname" id="firstname" placeholder="Name">
        </div>
        <div class="field mandatory">
            <input type="text" class="text-input mandatory" size="33" name="lastname" id="lastname" placeholder="Surname">
        </div>
        <div class="field mandatory">
            <input type="text" class="text-input mandatory" size="33" name="title" id="title" placeholder="Company">
        </div>
        <div class="field mandatory">
            <input type="text" class="text-input mandatory" size="33" name="function" id="function" placeholder="Function">
        </div>
        <div class="field mandatory">
            <input type="text" class="text-input mandatory" size="33" name="zip" id="zip" placeholder="Zip code">
        </div>
</div>
<div class="span6 last notopspace">
        <div class="field mandatory">
            <input type="text" class="text-input mandatory" size="33" name="city" id="city" placeholder="City">
        </div>
        <div class="field mandatory">
            <input type="text" class="text-input mandatory" size="33" name="country" id="country" placeholder="Country">
        </div>
        <div class="field mandatory">
            <input type="text" class="text-input mandatory" size="33" name="email" id="email" placeholder="E-mail">
        </div>
        <div class="field mandatory">
            <input type="text" class="text-input mandatory" size="33" name="tel" id="tel" placeholder="Tel">
        </div>
</div>                                      
<div class="span12">
            <textarea cols="78" rows="5" name="question" id="question" placeholder="Insert free text"></textarea>
            <div class="actionbuttons">
                <input type="submit" value="Submit" class="submit" id="formsubmit">
            </div>
</div>
{/exp:channel:form}

CHANNEL FORM SETTINGS: contactform> allow guest posts: Yes

i include the form as a snippet and i had to disable jquery as it gave conflicts.

the forms works via /home or /contact, but not via index

Answer 1

the action on the form points to http://syntetik.be/artilium-ee instead of http://syntetik.be/artilium-ee/ like the url