Ah no, sorry - I thought you were on Circle 2.0. Circle 2 uses a Docker image as a base machine to run builds, and these images are generally prepared and maintained by Circle employees. A number of breakages reported here come from a change in the latest version of these images.
Can you move to a Circle 2.0 machine or Docker configuration?
Mainly because Circle 1.0 is going to be discontinued, I believe in July. So you probably need to think about moving to 2.0 soonish - and if you need to do some fixing anyway, maybe now is a good time?
There’s some announcements in this forum, and on the blog, about this.