uddeIM 2.8 is currently not compatible with Joomla 3.0.
Do not try to install it. It will not work!
Joomla dev changed a lot of APIs, so lots of components will not work on Joomla 3.0. Some of the changes are listed here:
docs.joomla.org/Potential_backward_compatibility_issues_in_Joomla_3.0_and_Joomla_Platform_12.1
I am working on this issue but this will take some time. Maybe Joomla is really the wrong CMS to develop for because each version breaks the compatibility of the APIs. Users that use lots of components will have problems to upgrade to newer versions when this attitude will not change.
Update:
You can pull a very early alpha release of uddeIM 2.9 from the trunk on Joomlacode.org that installs on Joomla 3.0.
Most should work fine but currently you should expect problems with:
- Autocompleter
- RSS feeds
and maybe more features.
