This page describes how to install and configure Thunderbird with gpg under osx
It applies to Thunderbird v3.1, ENigmail 1.1.2 (Had been already installed in the profile previously) and from the GPGTools installer the following:

• MacGPG 2.0.17-9 (incl. gpg-pinentry and gpg-agent)
• GPGMail 1.3.3 (for OS X Mail.app)
• GPG Keychain Access 0.8.6 (managing GPG keys)
• GPGServices 1.5 (OS X text services menu for GPG)
• GPGPreferences 0.6 (GPGTools preferences, gpgmail autofix only)
• Enigmail 1.1.2 (for Mozilla Thunderbird)

Perform following steps:

1. install Thunderbird
2. start thunderbird-bin –profilemanager from the terminal
3. create a new profile: default
4. locate the default profile to the correct .slt entry
5. quit when done
6. start Thunderbird, check if it works
7. Install gpg via http://www.gnupg.org/documentation/howtos.en.html to the binary here http://www.gpgtools.org/
8. make a symbolic link to the GnuPG directory which holds all keys from the restored Backup/Email folder
   ln -s /Users/idx/Backup/Email/GnuPGP /Users/idx/.gnupg
9. locate gpg with the following command:
   which gpg
10. paste the result in Thunderbird in the following location: Tools→Add Ons→Extensions→Enigmail→Preferences→Files and Directories. Click on Browse and press Command+Shift+G to specify the path manually. Select from that directory gpg2.
11. Use from the terminal to check the keys with:
    gpg –list-keys
12. Use from the terminal to import keys manually:
    gpg –import filename

If initialization was not performed correctly, you could try the autofix options in GPGTools via the System Preferences.