Why the content of a block created in an external module does not appear?
call a php function to built block-content, in hook_view code should be:

//construct your output as a function    
$block['content'] = myfunctionname(); // this function is called 3 lines below
....
return $block;
//then call your output content function
function myfunctionname() {
$output = 'whatever you want(arrays, functions, html, more php, ....)'
 };
 return $output;


that will return $output as your content.