Error: Captcha plugin not set or not found.

Hi! i LOVE the Play Thru Captcha plug in and really want to use it! I have a js wright template (it's responsive) and I have Joomla 2.5.9 and I am just using the regular Joomla login page to register new people to my website: www.traintracts.com and I downloaded it and uploaded it to my backend and i did register with www.areyouahuman and I got my two keys and I copy and pasted them and plugged them in to set it up and I enabled it in the plug in manager and I disabled the other regular ReCaptcha that is there in the module manager and did what I thought is right or is usual...and I keep getting this error message: "Error Captcha plugin not set or not found. Please contact a site administrator" on my regular joomla register form ....and I am really stumped. Can you please help me? What am I doing wrong? I copy and pasted the Registration form into a MS Word in order to attach it. So please see attachment.
Thank you so much for your help!
I also read a similar post about "Installation" and followed his advice and so I went to "User Manager" and to selected "PlayThru Captcha" and saved it and so hopefully went back and tried it again and this time, there a a big blank space where the Play Thru Captcha should be....I don't understand why it is not working. I would so appreciate your help!

I had the same error message, but I had previously gotten PlayThru to work on my site with my Kunena forum registration. I was puzzled when I went back a few months later to see that my Contact Form didn't work. Followed all my previous steps and found one more place that needed attention. Here's that last step that got it working in my core Joomla Contact Form:
1) Went to my Contacts through the Contact Manager.
2) Found the Contact that works with my form and checked/selected the box. Not Edit.
3) Then clicked the Options icon in the top right of the admin page,
4) Went to the FORM tab. The first selection is a drop-down menu. Here I chose PlayThru instead of default. Even though I had already chosen PlayThru as default in Global Config, it didn't work.
5) Click SAVE and Close, then refresh the Contact Form page.

Hope this helps!

Great plugin - Thanks!!

I am also using a JS Wright Template, Impacto on Joomla 2.5.11