RealPort driver fails to install on Ubuntu 14.04.3 (error 1 at dgrp_net_ops)

I have reviewed the twp different methods of installing RealPort drivers. I had it working on ubuntu 14.04 with no issues. Using either method - RPM source with alien package, and ./configure - make all - etc… results in:

make[3]: *** [/home/user1/rpmbuild/BUILD/dgrp-1.9/driver/build/dgrp_net_ops.o] Error 1

The knowledge base references the same issue when installing RealPort on Kernel 2.6.26, however I was not able to find anything referencing this particular issue in Ubuntu 14.04.3

I recommend trying the latest beta release which addresses installation on newer kernels: