problem adding checkboxes and multi select box

I love this place!
I make some test with the custom press, adding some custom fields at directory listing, all be ok, but when I try to add a checkboxes or multi select box, on the post just appear array..
I don’t know what are doing bad.. Can help me?
My test is here: buscoautomovil.com/listings/huydai-sonata, look where say sabado, appear the word: array in the table..