Firstly, with this error, please try updating to Cakewalk v28.11.0.21 - having done so rescan the plugins from your plugin preferences of Cakewalk.
You can check for updates from the help menu of cakewalk.
If the update fails and the plugin itself will not open, you can also try the following:
Copy the VST3 plugin file from inside the recursive BBC Symphony Orchestra directory here:
C:\Program Files\Common Files\VST3\BBC Symphony Orchestra (64 Bit)\Contents\x86_64-win
and move up the folder levels to:
C:\Program Files\Common Files\VST3
Paste the VST3 file in this location and reload cakewalk / scan your plugins.