When you try adding a file to source control in Microsoft Visual C++, you may receive the following error message:
Unable to map local file <file path> to source control server project path.
When you add file A to source control, SourceAnywhere for VSS gets the file server path based on the local relative path of file A to the project file. So, if file A is too far from the project file locally, say they are on the different disks, the server path of file A will be beyond the server root($/). This will cause the error you are getting.
Please try moving file A to the folder where the project file resides to see if it solves the issue.