The only way I can see this happening is if you installed a ix86 RPM on a x86_86 system. You can do that and R will run, but you will not be able to build packages out of the box.
This is exactly what happened. Now I know to use 'uname -a' to check machine architecture first. I was able to install the x86_64 version and then packages successfully. Thanks very much, Scott Waichler