Sure this is not a requirement to install CCNet on a Server nor on the same machine as your repository.
CCNet can run as console application or windows service and both can run on windows, windows server and linux/mac with Mono.
Thus CCNet uses the native applications for source control operations (e.g. svn.exe or git.exe) it also supports the same remote repository features as its source control application. So your Subversion repository can be located everywhere your CCNet machine has access to.
I recommend you to read the Scenarios Section in our wiki.