The GXflow runtime client installs with GeneXus X setup, but only in two platforms NET - SQL Server 2005 and Java - SQL Server 2005. To execute a Business Process Diagram in the other platforms you must install the setup for the GeneXus version you have.
You can download from here:
Once you download it and execute you will see the following wizard to follow:
Clic "Next" to continue.
Enter <Usr_Name> and <Company_Name> and clic "Next".
Select the platforms you want to install and clic "Next"
Clic "Next" to start the installation.
The GXflow clients will be downloaded from the Internet and installed.