Boring adminstrative thing . . . I got a message t

Boring adminstrative thing . . . I got a message this morning: "I tried last night to make some lists but kept getting an 'HTTP 501 not implemented' error. This morning, I was able to get to the lists, but when I
clicked on the "save" button, I got the same error message." Has anybody else experienced this problem? The Listology code hasn't changed in weeks, so I'm surprised/alarmed to see this pop up out of the blue.