A recursive call is when a function call's itself, I believe.
function check() {
if (check()) {
echo "it's true";
}
return true;
}
Or something like that. I can't think of anything in IIP that would cause this. I'm not 100% sure but I don't believe I have any specific functions in IIP. It uses the .threads functions and classes. But I'm not 100% sure that it's not IIP causing your problems.
You should remove IIP and see if that corrects the problem. Knowing the version of Apache and MySQL and PHP will help others when trying to figure this out.
