activeCollab supports version control integration through the Source Module. Currently the Source Module only supports integration with the Subversion version control system.
The Source module is not installed by default. To install it, go to the Administration > Modules page and select Source module from list of Available Modules:
The Source Module uses a command line Subversion client to interact with repositories. Once the Source Module is installed, you'll need to configure the path to the Subversion command line client. To do that, go to the Administration page and click the Source Settings icon in the Tools section:
You must then provide a path to the folder where your svn client binary is located:
The settings page has a simple tool that lets you check whether the path you have inserted is valid and if activeCollab can interact with the command line tool. When a valid path to the Subversion command line client is provided, you'll be able to add SVN repositories to all of your projects.
More details on this issue are available in How to configure Source Module Tutorial.