Yes, I have seen that also for users on the new Mas OSX Mavericks. Here is a document I created for my users to solve that issue. I made changes by removing my VPN web address. Be sure to have them use the correct web address for your VPN webpage.
1. Go to http://www.microsoft.com/en-us/download/confirmation.aspx?id=18140 and download and install the Microsoft Remote Desktop Client for Mac. *Note: the install may require special steps, depending on the security settings of your Mac. (Click on the little question mark in the lower left of any popup window after trying to install to learn how to install third-party apps. It usually involves opening the file from Finder and holding the CONTROL key down while clicking and selecting Open.) Once it properly installs the app, continue to the next step.
2. Go to http://www.java.com/ and download and install the latest Java update for Mac.
3. Restart your Mac.
4. Open Safari and go to <VPN webpage> and log in.
5. Go to the SAFARI>PREFERENCES menu from the Dynamic Top Bar on your Mac desktop.
6. From the Preferences windows, go to the Security tab.
7. Ensure the check box is checked for Allow Plug-ins next to Internet plug-ins. Then click on the Manage Website Settings… button.
8. Ensure Java is highlighted on the left side, and then make sure <VPN website address> shows up in the Current Open Websites. Select Allow Always in the drop-down box to the right of <VPN website address>. Click the drop-down box again and select Run in Unsafe Mode. A popup window will pop up, click Trust. Click Done.
9. Now you can select any of the Mac 2 connections from the VPN page and it should now load Java properly and open the remote desktop connection for the resource you selected.