What you can download from www.dynamassist.com is a so called E-book. It consists of numerous Mathcad files usually referencing each other in a hyperlink manner. Prime does not support e-books. If you really are interested you could download the trial version of the current Mathcad15 and install it. Now you can convert the files (within the trial period of 1 month) - Mathcad15 must be installed for Prime or Prime Express to be able to convert files from Mathcad format (mcd, xmcd, xmcdz) to Prime format (mcdx).
I converted the one file which Vladimir posted in his answer for you in Prime4 format and attach it here.
It uses scripted components - a feature (like so many) not supported by Prime. You will have to replace the two list boxes at the top for normal assignments. Also the data output component at the end is not supported by Prime. You will have to write out the data by other means.
