PHP can be compiled, as in you can compile it to machine code and prevent a parsing everytime you access a file. That the way accelerator like APC work. But you can't compile it like a .NET DLL with every error checked in advance. It would go against its dynamic nature. Late binding mean it will always check for error at runtime
For your particuliar problem, I would suggest adding Unit Tests to your project. They are very good to have anyway, and they will help you catch error in your interface implementation. I personally couldn't live without them. You may want to check PHPUnit or SimpleTests.
EDIT To understand why PHP can't check your error, just check this snippet of code.
if ($_GET['impl'] == 'interface1') {
interface MyInterface {
function foo($var);
}
} else {
interface MyInterface {
function bar($var, $var2);
}
}
class Implementation implements MyInterface { //Will crash or not depending on the URL!
function foo($var) {}
}