You must have notices turned on in your local php.ini and not on your live.
The error is because you are referring to url parameters that don't exist when the page first loads. For example on the archive.php page you have:
$rsNewsletter->bindParam("s", "".$_GET['IssueMonth'] ."", "-1xx"); //varIssueMonth
$rsNewsletter->bindParam("s", "".$_GET['IssueYear'] ."", "-1xx"); //varIssueYear
In order to account for situations where the URL parameter doesn't exist, you should use:
$rsNewsletter->bindParam("s", "".(isset($_GET['IssueMonth'])?$_GET['IssueMonth']:"") ."", "-1xx"); //varIssueMonth
$rsNewsletter->bindParam("s", "".(isset($_GET['IssueYear'])?$_GET['IssueYear']:"") ."", "-1xx"); //varIssueYear
Turning off Notices in your php.ini would accomplish the same result since the value would be ignored.
