See the notes about .INI file mappings in the General Installation of Applications on WinFrame.
DP4 applications make use of the DP4 configuration file. Provided the above procedures have been followed, a copy of the configuration file will be copied to the Windows sub-directory of the user's home directory, allowing each user to have his own settings.
It is possible for each user to have their own copy of USERDATA.SYS. By default the copy of USERDATA.SYS in the installation directory is used by all users. However if a copy of USERDATA.SYS is placed in the users home directory and this is the current directory when the application is launched, the application will use this copy instead. One way to do this is to set the working directory for each DP4 program in the group to %homedrive%%homepath%. This should be done in "install" mode.