Found the problem.
It appears I seem to have uploaded the wrong version.
In order for you to get it working,
use backstage,
open the TiddlerEncryptionPlugin,
edit it, search for function
GetAndSetPasswordForPromptToDecrypt_TiddlerEncryptionPlugin(promptString)
then *Comment out* the two "DisplayMessage()" calls in that function.
This will get the plugin working, but the 'disable cache' facility
will not work.
I will update the web repositories tonight with the correct version.
My sincerest apologies for this mess up.
...Lyall