If, like us, you have recently updated to OS X 10.8 Mountain Lion, you may have noticed that your Coda application is no longer updating or accessing your SVN repositories. It seems Mountain Lion does not come with SVN, regardless if you've done a clean install or upgraded from a previous version of OS X.
You can test this by opening a new Terminal window and typing...
...in the command line. If you get a "command not found" response, then this is your problem. :/
We found a fairly painless solution over at superuser.com. Download the latest version of Xcode from the Mac App Store and, when it is installed, just go to...
Xcode -> Preferences -> Downloads -> Command Line Tools -> Install.
This should fix you up. Good luck!