CAPTCHA question

[comptech520]

On my website I have 3 forms with CAPTCHA.

The problem is when I submit the form and use the correct registration code, I get this error:

The registration code did not match the one displayed, a new code has been generated, please try again.

I have tried removing the cache from my browser, rebooting my server and adding the following lines of code to the top of my page:

<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
<META HTTP-EQUIV="Cache-control" CONTENT="no-cache">

Still no luck, does anyone have any experience with this?

[bokeh]

echo '<img src="captcha_script.php?force_update='.time().'">';The variable is not used by the script but makes the browser understand the resource is different relative to the previous load.