Wonomyro, autosomal components can drastically change thru few generations. We cannot expect west Serbs to plot near Aromanians or Albanians. Not that Krajina and RS Serbs have only higher E1b in compare to Croats, Bosnjaks and Slovenians, but what i already explained in addition to E1b there is significant J2-M205 portion in them. J2-M205>Y22059 is connected to Montenegrin Latin speaking tribe Krici, it is clear Middle Eastern Roman signal that for sure was Latin speaking Vlach prior to identify with Serb.
What is interesting is that there is almost no J-M205>Y22059 in Croats, Bosnjaks and Slovens while majority of Serbian J2-M205>Y22059 is found exactly in Croatia and RS in Bosnia. According to Serb project J2-M205 and Ev13 are 30% in Lika. They must have been Orthodox Vlachs, that because of their religion later identified with Serbs rather then with Catholic Croats.
Also note that Slavic haplogroups could eventually always come in while Vlach ones could not. Even this Vlach signal that we find today in them is significant. Its not enough to call them Vlachs for sure, but enough to verify that at least one part of these people was Vlach before.
Look at J2-M205 samples from Serb project, its not evenly distributed among them but rather on two hot spots both known for Vlach settlements.