Player is invisible, and "cannot convert Fixnum into String" error

Hi!!! first time using RPG Maker XP and Pokemon essentials. Play test was running fine a bit ago. tried creating events for entering doors and what not. Went to test play again, Sprite is invisible?? dont know how to fix this. and i always get an error when i try to enter any door and the game quits

this is the error i get

---------------------------
Pokemon Essentials
---------------------------
Exception: TypeError

Message: cannot convert Fixnum into String

PokemonField:1532:in `+'

PokemonField:1532:in `pbGetPlayerCharset'

PokemonField:1548:in `pbUpdateVehicle'

PokemonField:1559:in `pbCancelVehicles'

Scene_Map:225:in `transfer_player'

Scene_Map:110:in `update'

Scene_Map:101:in `loop'

Scene_Map:114:in `update'

Scene_Map:68:in `main'

Scene_Map:65:in `loop'


i would really like some help i feel very confused and lost

I had that error long time ago too.
This happens because you haven't defined a character for your game, or if you deleted the intro map.
In your starting map, you should do an autorun event with the script:

Boy:


Girl:


Or you can simply edit the Intro Map.