No $_POST data in callback from PayPal

Question

I'm integrating Standard PayPal payment via NVP. I've created everything, but my problem is that on my complete page PayPal doesn't return any $_POST and $_GET data. Even, so I put rm=2 in my request to PayPal. That's totally odd. As I have checked my old PP integration as that also doesn't return any data. But I have checked it only on my localhost. Any idea? As that seems to me for PayPal issues.

Part of my call to PP NVP below:

'PWD' => $password, 
'USER' => $user, 
'SIGNATURE' => $signature,
'METHOD' => $method
'BUTTONTYPE' => 'BUYNOW',
'BUTTONCODE' => 'HOSTED',
'BUTTONSUBTYPE' => 'PRODUCTS',
'BUTTONCOUNTRY' => 'GB',
'BUTTONIMAGEURL' => 'https://www.paypalobjects.com/webstatic/en_US/btn/btn_buynow_107x26.png',
'L_BUTTONVAR1' => 'return=' . $this->getReturnUrl(),
'L_BUTTONVAR2' => 'notify_url=' . $this->getNotifyUrl(),
'L_BUTTONVAR3' => 'invoice=' . $this->getInvoice(),
'L_BUTTONVAR4' => 'currency_code=GBP',
'L_BUTTONVAR5' => 'item_number=1',
'L_BUTTONVAR6' => 'item_name=' . $this->getItemName(),
'L_BUTTONVAR7' => 'amount=' . $this->getAmount(),
'L_BUTTONVAR8' => 'cpp_header_image=' . $this->getHeaderImage(),
'L_BUTTONVAR9' => 'rm=2', // return data by POST method