[Plugin: Contact Form 7] Customized submit button broken

I have a contact form that is step 2 of 4 steps. Users fill out the information, then click on an image “Next Step” which used so 2 things happen: submit the contact form 7 information and moved the user to the next page (step 3). I updated the theme and plugin stylesheets with

.nextbutton {
	background-image:url(/images/next_button1.gif);
	background-repeat:no-repeat;
	width:133px;
	height:51px;
	float:right;
	margin:0px;
	padding:0px;
	border:none;
	cursor:pointer;

On the step 2 page (step-2 ) the image of the button shows up just fine, but clicking it does nothing.

In the contactform itself, the code for the button is:

[checkbox tocagreement " I Agree to the Terms and Conditions"]</h3></strong>
<p>You will receive a confirmation email after clicking the "Next Step" button.</p>
<div style="float:left;"><a href="/upload-e-books/step-1/"><img class="alignleft" title="back_button" src="/images/back_button.gif" alt="Click here to go back a step" width="133" height="51" /></a></div>
<div style="float:right;">[submit class:nextbutton " "]</div>

I’ve looked through the posts and found HOW to do this, but not how to fix it when it is not working.

I have tried the button in the latest versions of Firefox, Safari, and Chrome with no success.

https://www.ads-software.com/extend/plugins/contact-form-7/