Could yo please try out this steps before going through the following.
- Launch Reaper & a new instance of ANA 2
- From ANA 2's GUI select "Init Preset" --> 1
- Click on the name -INIT- to open up the presets browser --> 2
- Click on "Refresh" in the browser --> 3
- Then remove this instance of ANA 2, close Repaer, reopen it and launch a new instance of ANA 2 and give it a try.
If that doesn't help, then make sure that the installation was correctly done.
When you have installed ANA 2, did you only run the 64bit installer and not both x32 & x64 installers ? Make sure that you haven't got any 32bit VST plugin installed, the default install location is - C:/Program Files (x86)/Steinberg/VSTPlugins/ unless you use a custom path for your 32bit VSTs --> if you find a ANA 2.dll within your C:/Program Files (x86)/.... then remove it.
There's also a manual uninstall support thread that you can follow, if the above did not work, then follow the uninstall procedure, reboot your PC, run Reaper once then close it and make a new installation, making sure that you're only running the x64 installer.
Other hints that can help : It's good to make sure that your downloaded .zip archive for ANA 2 didn't get corrupted, so make sure to download it again from your user account. Use a reliable un-archiver such as Winrar ( there's a free version ).
Hope this helps, let us know 
