I'm trying to build a deck, but as I'm doing so, the counter at the bottom doesn't add up correctly. I have approximately 30 cards showing for the FP side of the deck, but it says at the bottom I only have 12 cards on that side. And when I hit Save and come back to the deckbuilder, that deck is completely blank.
Seems both your game-play and deck building is messed up. If I had to guess - it would be either very unstable connection, or a malicious browser plugin interfering with browser-server communication.
I can only help you out, if you provide me with the output from JavaScript console, whenever the program is acting up again. In Chrome it's in Tools->JavaScript console.