[Enigmail] can not query passphrase in batch mode

[Stefan X]

Hi!
I am using Enigmail for several years but recently I ran into trouble. I 
have two secret keys and created a third one with Enigmail. Since that 
time I am not able to decrypt any email anymore. The output of 
Enigmail's console is following:


enigmail> C:\Program Files\GNU\GnuPG\gpg.exe --charset utf8  --batch 
--no-tty --status-fd 2 -d
gpg: Passphrase kann im Batchmodus nicht abgefragt werden [which means: 
can not query passphrase in batch mode]

[Some info about the actual e-mail is following.]

gpg: Entschlüsselung fehlgeschlagen: Geheimer Schlüssel ist nicht 
vorhanden [which means: decryption failed: secret key does not exist]
enigmail.js: Enigmail.decryptMessageEnd: Error in command execution


All of my keys are now passphrase protected. The third key had no 
passphrase protection before but I changed this in hope to fix the 
described problem.

Any ideas?!

Stefan