September 2015 update : This article is still obsolete. With the adoption of Bootstrap into the Joomla system conflicts through multiple versions of jQuery being installed are largely a thing of the past, but they do still occasionally appear.
Once you've identified the problem, you're then advised to contact the suppliers of that software and ask them why it doesn't work with jQuery running in noConfict mode.
History of the internet and everything
Pretty soon folks realised that lots of these libraries were incompatible with each other because they use the same function names, or the same object names or for some other obscure reasons that to this day we still don't understand. Joomla, being the great big melting pot of creativity that it is, is a classic example of this because of the huge number of technologies people use to achieve solutions and the willingness of those folks to share those solutions.
How this affects Jomres
Historically Jomres, which was written using the jQuery library for AJAX back when Joomla 1.0.x was new, used to have problems with the mootools library in Joomla but this has, to an extent, been licked by calling first the jquery library then jomres.js and defining var jomresJquery = jQuery.noConflict(); on the first line of jomres.js.
How do I know that I've got a problem like this?
How do I debug this then?
Some other common problems
I'm not going to go through all of the errors that I've seen over the years (my memory's not that good) but I will enter here some that have cropped up recently.
Jquery being defined by a template, errors in the booking form can look like:
jQuery.jheartbeat is undefined
This has become a bit more common recently as several template designers seem to be using jQuery quite a lot nowadays.
To resolve this there is an option in the Jomres Site Configuration -> Misc tab called "Load Jomres jQuery library?" Try setting it to No.
If using this option doesn't work there are two ways you can fix it (three if you choose to use another template).
Edit out the calls in Jomres and rename all the calls from ''jQuery'' to (for example) ''$jQuery''. Don't, please, just don't try this. jQuery is used so extensively within Jomres you'll be bald or grey or quite insane long before you've finished doing this.
Edit the template to
Remove the calls to it's own jQuery library, trusting it to use Jomres library (if a Jomres module however isn't called on every page of your site then you might, depending on the template, need to instead of removing the call, put in an ''if'' statement so if you're not on a Jomres page then it includes it's own call to the jQuery library