Regarding above comment:
And please do NOT install AmiBroker plugins at all.
Correct and up-to-date plugins come pre-installed during normal AmiBroker setup procedure.
Per @Tomasz comment, the IB data plugin is shipped with current versions of Amibroker and ready for use. This plugin enables an API to retrieve data from IB.
However, I believe (@Tomasz please confirm this), in order to place orders from Amibroker, I had to first install AmiBroker Auto-Trading interface for Interactive Brokers.
During the install process (i.e. executing the download: at1380beta.exe), I found it necessary to change the target installation folder to c:\program files\amibroker as shown in the image below. This created a BrokerIB.exe file in the target folder, which was not previously present. Note that this is NOT A Plugin. I just wanted to clarify this for future readers.