How to fix Image verification issue at site registration

[ppatil007]

Please refer attached image
site: http://zonedesi.com/register.php (vBulletin 4.0.6 Patch Level 1)
Problem : Registration image does not load at all hence no user can register. If I remove image verification I get loads of spammers

I have not made any changes to my site for over a year, the image verification was working fine until 2 weeks back. I was trying to research online to see the cause and how to fix. I tired many things but nothing seems to be working.
Please guide me to resolve
[img=http://s7.postimg.org/4mziw3f2f/Capture.jpg] (http://postimg.org/image/4mziw3f2f/)

[Dave]

Have you considered a different kind of human verification settings? Google reCaptcha for example is another option in vBulletin's settings.

[ppatil007]

Have you considered a different kind of human verification settings? Google reCaptcha for example is another option in vBulletin's settings.

Only 1 type works (reCAPTCHA) not the generic one (Image Verification) does not work

reCAPTCHA output sometimes is crazy even humans cannot figure out the letters

[ppatil007]

updated the PHP version it solved the problem !