NewBee - Espruino upload/download error checking?

I think is a problem loading the stored program

Ahh - that's almost certainly it. Same problem you have on other boards if you don't do a full erase when you flash.

Espruino figures out about built-in classes by storing a pointer to the constructor function - unfortunately every time you use a new firmware it's pretty likely that the pointer changes, so it will forget that 'process' included the function! Trying delete process and the trying again might fix it.

It's probably just as well that something so obvious breaks - there are loads of other more subtle things that could break as well!