With newer versions of SuSE Linux, the kernel sources need to prepared and symbolic links are needed for the ncurses library:
1. ln -s ncurses/panel.h panel.h in /usr/include
2. make oldconfig in /usr/src/linux
3. make prepare in /usr/src/linux
4. make scripts in /usr/src/linux
5. cp /usr/src/linux-obj/Module.* /usr/src/linux
6. rpmbuild --rebuild dgrp-(version).src.rpm
7. rpm -i /usr/src/packages/RPMS/(architecture)/dgrp-(version).(architecture).rpm
Where version is the Digi RealPort driver version you are installing and architecture is the system architecture (i.e. i386, x86_64, amd64, etc..)