Hi,
It seems that this could be an issue within the API client. So this has nothing to do with i-doit itself. I recommend to raise a new issue. While doing so please post some more information, e. g.:
API client version
Complete output of make initialize
Used PHP version and operating system
I am able to reproduce your second error with the latest version of the API client and PHP 7.0.8 (Ubuntu 16.10).
Greetings,
Benjamin