Joomla 1.6 Error: "The URL is not valid and cannot be loaded"

Testing Joomla 1.5 and a few initial observations:

Almost everything is the same with older versions of Joomla, except for the look and feel in the administrative interface, nothing really different that needs much adjusting

However, enabling all default (that come with the package) modules and components as part of the test, a "The URL is not valid and cannot be loaded" dialog box error is displayed when refreshing the frontend page. And when clicking OK, the page is otherwise ok and displaying properly.

Don't be alarmed as this is not an issue really. The ff. can be noted which will resolve the error:

Culprit:

Wrapper module is published but has no URL specified to wrap. Earlier Joomla 1.5 versions has the wrapper module published or enabled by the default installation, while the latest Joomla 1.5 to date has this disabled.

Error/s:

"The URL is not valid and cannot be loaded" in Firefox. In IE7, page will simply not display. In my case, the error was visible immediately while in some this may not take effect immediately as your site will seem fine for a few days after installation, and will pop eventually.

"The address is not valid" is also displayed in Internet Explorer 7 when the sample data is deleted (when one needs to put in the real stuff).

Solution:

Fill in valid URL in the wrapper module, otherwise disable or unpublish the module until desired.