I don't see any semicolons, Daragh, and the code you posted (putting time()+3600 in quotes) wouldn't work, as time() wouldn't be parsed. I haven't had this problem, but if you've seen people playing with quotation marks, maybe the following would work:
$expire = time() + 3600;
setcookie("TestCookie", $value, "$expire");
I wish I could be of more help, but I'm sure someone else here can.