The Af-Arch framework is conformed by a set of libraries and tools. They are license using different licenses.http://www.gnu.org/licenses/licenses.html#LGPL.
Main implication about LGPL license is that you can develop closed source (known as commercial) application (as well as Open Source application) which links against LGPL libraries. This is because LGPL doesn't have the copyleft property.http://www.gnu.org/licenses/licenses.html#GPL.
This license covers: Af-Kernel (Af-Arch central server), aspl-clm (A command line tool to admin Af-Arch services) and af-gen (the Af-Arch IDL compiler).
Source code generated by af-gen tool can be released under the license you may chose.
In fact you are wellcome to develop commercial applications as well as Open Source based applications with no restrictions (of course only those ones applied by the license terms).
It would be appreciated to make a reference to the Af-Arch project but it is not requiered.
You can link your propietary application with the libraries (which are LGPL) but you must provide the full source code for the Af-Arch libraries or a reference on how to get them.
Because you don't link with the GPL tool you can install them with you propietary product (aspl-clm may be a good example). Again you must provide the full source code for the aspl-clm or a reference on how to get that code.
If you modify any piece of code inside the Af-Arch enviroment you must provide those modification with the application. It would be really appreciated to integrate that modifications inside the main Af-Arch branch.
Another issue to keep in mind on propietary applications is the Cygwin enviroment. The Af-Arch license schema makes somewhat incompatible to use the Af-Arch enviroment with Cygwin platform to develop commercial applications. This ecause Cygwin license is GPL (even the libraries: cygwin1.dll).
As a consecuence you may be able to compile Af-Arch under the Cygwin enviroment but you will have to chose the GPL license for you application.
To avoid this problem, for those commercial development, you can use MinGw (http://www.mingw.org) environment.