Resolution:
The SmartSockets Product Family (RTworks) client libraries for Solaris were built on Solaris 2.6 which used the libXm.so.3 version of the Motif library.  Starting with Solaris 2.7 and higher the default Motif library is now libXm.so.4.  In the rtlink script the linker option   libXm  is set to -lXm which causes it look for libXm.so which is a symbolic link to libXm.so.4. Although custom client applications can be linked to the newer libXm.so.4 without any link errors, the Warning shown above will be seen and runtime and no views will be loaded.

Since all the standard RTclient apps will also want to be using libXm.so.3, and since the rtlink script is used by all the other rtlink* scripts (like rtlinkhci), then the only thing that needs to be done is to edit the rtlink script as follows:
        Find the line    libXm=-lXm
        Change it to    libXm=-lXm12

This has been verified on Solaris 7,8,9, & 10.  The only potential problem that making this change might cause would be if you were also using rtlink to build client applications that need to use libXm.so.4. In that case the work around would be to create copies of rtlink and rtlinkhci called Xm3_rtlink and Xm3_rtlinkhci. Edit the last line of Xm3_rtlinkhci to execute Xm3_rtlink instead of rtlink, and then make the change described above in Xm3_rtlink. You would then continue to use rtlink to build your user-defined clients and Xm3_rtlinkhci to build custom versions of the RThci.

I see the following error when I try to run a custom HCI built using Solaris 2.7 or higher:WARNING: Unable to get/create drawing area in ThciLoadViews