[eluser]WanWizard[/eluser]
From what I can read about UDT, they're small snippets of code that create some output. You then use the UDT in a template.
You can not include CI that way, the CI front controller expects full control of the environment. Especially in a PHP4 environment.
In this particular case it references a variable created by the front controller, which is expected to be global. Which is not the case when you start including.