echo() and flush()

[Luth]

I have a PHP script that does various mysql queries, and at the very end, echos a return message to the browser:

echo($ret);
return;

Most of the time, that works fine. But sometimes, for some return messages, it just hangs up and wont echo anything. So I put:

echo($ret);
flush();
return;

And it worked, but now there's an extra "\n\n0\n\n\n" (newline chars, zero, newline chars) thats echo'd out. Whats causing it, and how do I fix this problem?