You have two (for want of a better term) "primary" libraries (although your posted code only uses LibDBIcon)
- LibDBIcon -- Creates manages the minimap button
- LibDataBroker -- Helps creating plugins for addons like TitanPanel.
Both of these use (depend on) LibStub (a library for managing library versioning) and LibCallBackHandler (for handling callbacks).
If your included a libraries depend on another library (or more) then the "sub-libraries" also need to be included in your addon and listed in the .toc (or via an xml file that does this).
Other addons may also use/include the same libraries (and sub-libraries). The loading of these is managed via LibStub.
Code:
<Ui xmlns="http://www.blizzard.com/wow/ui/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.blizzard.com/wow/ui/..\FrameXML\UI.xsd">
<Script file="LibStub\LibStub.lua"/>
<Script file="CallbackHandler-1.0\CallbackHandler-1.0.lua"/>
<Script file="Libs\LibDBIcon-1.0\LibDBIcon-1.0.lua"/>
</Ui>
Only include LibDataBroker-1.1 if you are actually using it (maybe you are, it just wasn't it the code you posted).