Bad BRConfig.sys drive specification or drive/path specified is invalid. Error 4180 will provide only a warning, along with diagnostic information. This error indicates that the second parameter of a drive statement does not refer to a directory. Error 4180 displays the path that BR! is attempting to verify but cannot find.
Error 4180 can also occur for any other syntax error in your Drive statement, for example a missing third parameter. (The third parameter has to be there, and it can't be blank.)