Uncaught TypeError: Cannot set property 'classRules' of undefined

jQuery is in drupal core, so you shouldn't have to add it manually, or how are you adding it?

Clientside Validation wouldn't work at all if jQuery isn't present, so my guess is you're adding jQuery twice.

Yeah, I'm having the same trouble. Tried both manually loading into my theme ini file and then just through the jQuery Update module with no luck.

Using jQuery-1.8.1 manually and used jQuery Update (and not with 1.5).

EDIT: The theme I have is loading jQuery twice it seems. I went ahead and installed the dev version of jQuery Update (pulls jQuery 1.7) and the Clientside Validation works like a charm, but the slider I was using now doesnt work.

Is there any method (a good method) to load two versions of jQuery?

Thanks

Loading 2 versions side by side is possible, see http://drupal.org/node/578712, but it means you have to add some custom javascript to make it work together.

Hello,
Recently I have purchased a theme (TouchM) and looks like the same error (Cannot set property 'classRules' of undefined ) throws up for client side validations after i enable the new theme. The validations work fine when i use the default bartik theme.
Please find the following libraries that is being used by this theme:

javascripts/foundation.min.js
javascripts/modernizr.foundation.js
plugins/slider-revolution/jquery.themepunch.plugins.min.js
plugins/slider-revolution/jquery.themepunch.revolution.min.js
plugins/flexislider/jquery.flexslider.js
javascripts/jquery.tipsy.js
javascripts/jquery.carouFredSel-6.0.3-packed.js
javascripts/jquery.touchSwipe.min.js
plugins/titan/js/prettify.js
plugins/titan/js/jquery.titanlighbox.js
javascripts/jquery.isotope.min.js
javascripts/app-head.js
javascripts/app.js

Any suggestions ?

Thanks.
Ajay

just had the same error after updating to 7.x-1.37

after a bit searching it turned out that this module can not be used alongside with timelineJS. no idea why. excluding clientside validation on the affected pages fixed the error.