That's weird, so far the games have been the best way I have gotten the currency from. I did get a bit from quests, but they don't seem to be as sure fire and usually require some item to be bought first.

The games and a few quests are the only way to get shards right now, if you're not getting payouts from the arcade games that's a bug and you should report it in the technical support forum. A daily quest from Lycus, 'That doesn't make any cents", is a good way to get around 200-500 shards a day, and some of Piper's hourly quests give shards for just playing a game.

The error messages are given short explanations from one of the Announcement/Bug Fix posts from a couple days ago. Definitely check those out and post in the Technical Help forum if you can't figure out a reason!

Default suggestions: Try it with a different browser, make sure your login is working (disable cookie blockers, AVG web, etc), clear cache and log back in...

I did try doing all those things--unfortunately it only worked on my phone and I can't play on my phone well for many reasons so...

I'll try looking into quests.

I wish there were more ways period because I hate playing flash games and the ones they have get super boring. I have never been a fan of matching games...

We do have a few more ways to earn shards planned, we also just tend to have a very long TO-DO list at any given time ^^;
Once we get Cooking up and running however we will be able to hit these other features a lot faster.

Stuff like more social rewards, user shops and more quests will help with getting more shards into your guys hot little hands.

I had that same bug for awhile! I decided to only try playing after an update happened on the site, and after the latest one I was getting rewards again! Maybe try again and see if the bug has been fixed for you too? If it's not you can always try starting your own trading thread and see if anyone wants items that you have.

And, like Club said, there's still more things to come! :)