CNSeg no method coercing S4 class to vector
If you are using the latest version of Bioconductor you should always look at the latest documentation of the package in Bioconductor. There could be changes from 2011 to 2018 (In this case there aren't any changes in the section you mention).

The problem is the package doesn't define how dist should behave with that object class (filteredrs is a RS object if I read the source code well). 

You can extract the metrics to calculate the distance yourself or ask the maintainer to add this method to the class. However it could be that the maintainer answer you if you post the question in the support site of Bioconductor.