mIRC will only execute one script for each matching event (in each file).

Combine the on text events and use if / elseif to parse the correct code block.

For example
Code:
ON *:TEXT:!VineWhip:#: {
  if ($nick == %PBPlayer1) {
    if (%PBPlayer1Poke == Bulbasaur) {
      ; code ..
    }
    elseif (%PBPlayer1Poke == Ivysaur) {
      ; code ..
    }
    elseif (%PBPlayer1Poke == Venusaur) {
      ; code ..
    }
    ; etc ...
  }

  elseif ($nick == %PBPlayer2) {
    if (%PBPlayer2Poke == Bulbasaur) {
    }
    elseif (%PBPlayer2Poke == Ivysaur) {
      ; code ..
    }
    elseif (%PBPlayer2Poke == Venusaur) {
      ; code ..
    }
    ; etc ...
  }

}