What changed just before you started getting the error? Did you perhaps update DateTime?

To try and fix the worst aspects of .dll hell and as a security measure Windows is much fussier about .dll management than it used to be. Generally that means .dll files have to be installed using a .msi installer (or other 'proper' installer). A work around may be to install the required .dll in your Perl bin directory.

However, this issue is most likely a bad build of DateTime, or a result of an uninstall of something that has removed that .dll and probably others. In either case this is likely to be the tip of the iceberg and more trouble will follow!