Yes, the template people are correct, MetaMod Pro has to override the module helper class in order to do its magic. Despite a number of approaches to the Joomla core team, they have never agreed to make the changes necessary for MetaMod (and other similar systems) to operate.

A few of us including NoNumber.nl (Peter van Westen) and Joomlart discussed together a joint change that we could all make that can override that class and provide the required functionality by means of a set of plugin points. Because of this joint venture, people can use any of our products together without clashing, because the extra magic is done in plugins by way of an agreed API. I wish that more extension developers would join us and prevent clashes as each developer adds some of their own functionality to the class and overrides it.

Do you have any idea if it is the Virtueplanet template or indeed Virtuemart that is the other extension overriding JModuleHelper? Or perhaps it’s a different extension entirely?

It can take a little bit of exploring to find which other extension it is that’s doing it. Usually I grep through the source code of the entire site for the text “JModuleHelper” and that comes up with something. If you can do that and let me know what extension it is, then that will go some way to finding a work-around. The last time I did this I found it was a plugin that wasn’t even needed on the site, so it was easy to turn it off and problem solved. If on the other hand it’s the template itself, then it might be more difficult, but let’s cross that bridge when we come to it. Perhaps could you e-mail me a copy of the template installation package?

Please let me know how you get on.

Before I forget, I also read somewhere that the re-ordering of the plugins can make a difference.