Problem with the printing

Hello all.
I was start last week using my printer Inkspirer.
In my first printing model i have problem with the quality.
My model was bulid from a few several lumps and saved in stl. file.
After the printing in places where the lumps are overlap was printing hole like in pictures.
It is hapend somebody?


Can you provide files for the model, please? This specific wall might be too thin, thus it is not being printed properly.