Migrating your Visual SVN from one server to another is reasonably straightforward if you do the following things:-
1. Install VisualSVN on the new server
2. Import the repositories from the old location
3. Change your settings in your subversion client (e.g. TortoiseSVN to point to it.
DO NOT be tempted to copy across your current repositories folder. When Subversion creates the repositories folder, it also sets permissions required. Copying across your current data obliterates the permissions. Yes, that’s what I did