The drpacs pipeline is a suite of (shell and python) scripts and the infrastructure to set up and run these scripts. Note this is a very general way to run pipelines on a organized set of data, and is not specific to PACS or MIRIAD.
It has to be installed together with dependencies such as MIRIAD and to some extent python+matplotlib and NEMO (at least for PACS). Details can be found in Appendix A of Ashley's paper. Here's a draft link: 
It is strongly recommended to contact Peter Teuben if you plan to use/install drpacs