There is no real error in the page but how it is presented seems to be a bit outdated. When the F1 concept was new and not everybody where familiar with the terms, this was more relevant information.
Especially the pictures are not that up-to-date when it comes to style and design
The Logical Unit (LU) is the basic building block for implementation of the OLA structure. It resembles, and is closely related to a class in Object-Oriented terms. An LU is created to define a business object such as a Customer, Inventory Part, or Customer Invoice, for example. Part of the LU definition will be attributes and behaviors (methods) for that business object. Relationships to other LU's are specified as well.
An LU is defined and implemented across all three layers of the OLA model. A
typical LU will consist of an Oracle table in the Data Storage Layer, PL/SQL
Procedures and Functions and an Oracle View in the Business Logic Layer, and one
or more Application Forms in the Presentation Layer.
In the example below, a business object, Customer, is modeled in Rational Rose
as a class. Attributes and methods are also modeled. The model is used to create
the definitions for the Data Storage Layer, the View and Package for the
Business Logic Layer where additional functionality for this business object
will be written. The Presentation Layer will provide one or more graphical Form
type Windows objects for interacting with the middle layer. All of these parts
together comprise the Customer LU
LU Attributes are represented by columns in the Data Storage Layer table. Instances of the business object represented by the LU are stored as rows in the table. One customer would represent one instance, for example. Methods for the LU will be packaged together in an Oracle structure called a package, also referred to as an API (as in Application Program Interface) in Foundation1 terms.
LUs communicate internally (between layers) and with other LUs by way of messages. In some cases, a message is a direct call to a method with parameters. In other cases, a message is constructed and 'sent' to the other LU.
Additional information about Logical Units in the architecture context is found in the Foundation1 Overview.