Ofcourse in some cases you are right about the name Publio misspelled as Plubio. But it seems, that the name Plubio really exists, not only as a misspelling. Just Google on it, I cannot imagine people on Facebook misspell their own name.
Both Publio and Plubio are given on this list of Spanish names:
http://en.wiktionary.org/wiki/Appendix:Spanish_given_names
According to these sites, the origin of Plubio (not Publio) is Greek, meaning "man of the sea":
http://www.rede2001.com/nombres/p.htmhttp://www.babynamescountry.com/meanings/Plubio.html