Error establishing a database connection

Last night I went to post to my blog (www.andydduncan.com/blog) but kept getting an error saying that my info in my wp-config.php file might be wrong or my host’s database server might be down. Here’s a screenshot of the exact error. My host is Dotster, and this is the second time within a month something has gone wrong (the first time my server was down, and this time I’m not sure at who’s end the problem lies).
Thanks for any help