I recently set up a repository using VisualSVN Server. It uses Windows Authentication. Some users are having problems committing projects to the repository. (They have no problems checking out repositories).
The BUILTIN\Users group has read-only access for the entire repository and the individual users have read/write permissions setup (from the VisualSVN Management Console) for the folder that he is trying to commit to.
We've checked the URL for casing issues (which seems to be the main solution that I've seen) and everything looks correct. Do the user account/group policies settings affect the authentication?