Here are a couple more things you can try:

http://202.52.136.82/

That's the server that www.skritter.cn used to point to, but we tried switching out since people were having trouble connecting to that one too. Maybe you'll have better luck.

http://96.126.102.247/

That's the direct link to the server www.skritter.cn and www.skritter.com now point to. If this works, then for some reason our DNS server is not accessible in China, or at least certain parts of it, sometimes.

Have you tried connecting from other computers? Such as at others' houses, or at an internet cafe, or any other public computers that use other connections that are available?

Skritter's bandwidth demands should be pretty low according to my testing and calculations. Do you find that it really eats up a lot of bandwidth to Skritter on a VPN? We might be able to reduce the bandwidth requirements if so.

You may want to look into an alternative VPN - my impression was that the reasonable ones charge for a block of bandwidth per month (e.g. 5 GB), not time. Being charged by time is just ridiculous.

Astrill's a great option, many different proxies to choose from if one happens to be slow, and unlimited bandwidth!