I've been playing (/lurking) for a good couple of months now, so I thought I'd try to use my HPP to give ugrading a try before I commit to a paid upgrade.

According to the Cash Shop, I have 5HPP. But when I try to Upgrade with Referral Points, I get an error saying I don't have enough points to complete the upgrade. Halp! ;_;

5 HPP ≠ Referral Points, unfortunately! They are two entirely different currencies, hence why it isn't going through. Sorry :(

Siren is correct.  They aren't the same currency.  When it states Referral/Achievement points in the cash shop it's combining your HPP and referral points to purchase things in the cash shop.  You can see how many referral points you actually have on your home page on the left side between player points and chat lines.

If you do not want to play RLD for an upgrade you could always refer 5 people to get your 5 referral points or sell coding/graphics/training services/etc to gain HPD and buy an upgrade that way! ☺

Participating in Club contests are also a great way to earn some extra hpd too! :)

Thanks all!