In that context, it would most likely be some measurement that would allow you to choose a different yarn and make sure it's suitable to the pattern.
The two recommended yarns each have 131 yards (120m) in a 100g ball. (Source: the Ravelry pages for Yarn Art Dolce and Himalaya Dolphin Baby.) That falls into a range of 100-150 yards per 100g. If you chose a similar style of yarn, made from similar materials, that had between 100-150 yards per 100g, you would get similar results.
I would further guess that the pattern was not originally written in English, and the abbreviation "rp." is an untranslated abbreviation from the original language. I sometimes translate knitting and crochet patterns, and it's easy to miss an abbreviation when translating. If you know the original language of the pattern, or provide the name and source of the pattern, it might be possible to sleuth out what the abbreviation stands for.