last time i checked PayPal was not working here in Qatar. You can access and use the site but you cannot add a bank account/credit card/pay card from qatar.
Be very careful with what you are doing. I suggest checking if the website from which you want to buy supports CashU. If they do then make an account on cashu.com and copy the account number and username. then go to UAE-Exchange and tell them you want to add balance to your cashU account. They will ask for your account number, user name and phone number. Make sure you copy the right details.