You can fix it when you follow the FAQ or the posting above.
Nevertheless it seems that you are still using an older module, plugin or CB plugin from a previous uddeIM version because of the "redeclare uddeimmodcheckcb" error.
This error appears when one plugin, module, or CB plugin from an previous version is mixed with the most current version of uddeIM.
I guess that it is the CB PMS plugin that has been installed twice (it has been renamed in uddeIM 2.6 package, so some people have still the old one installed and installed the newer one additionally).
The uddeIM specific tables should be installed or do you still get the db error? If so you have a serious problem with your site. Reinstall Joomla in order to get a working site and install uddeIM on that clean system.
uddeIM & uddePF Development
CB Language Workgroup
CB 3rd Party Developer