To reproduce the bug (you can substitute anything, **including valid data** for 'none' in the following):
0) from console rm -rf ~/.mozilla-thunderbird
1) launch thunderbird
2) Import wizard: Don't import anything
3) Account wizard: Email account
4) Name: none, email address: none@none
5) Server information: IMAP, Incoming: none, Outgoing: none
6) Incoming username: none
7) Account name: none@none
8) Finish
9) (Alert, failed to connect to none -- this is as expected)
10) press WRITE ---> 
"An error occurred while creating a message compose window. Please try again."

I tried it all with valid, DNS-resolvable server names.

----
The bug did not appear right away when I did not use the Account Setup Wizard for creating the initial account at first launch -- temporary workaround:

0) from console rm -rf ~/.mozilla-thunderbird
1) launch thunderbird
2) Import wizard: Don't import anything
3) Account wizard: CANCEL, confirm with EXIT
4) press WRITE
5) Account wizard appears, proceed as in 4)-8) before
6) open/close compose windows **works as expected**
7) when thunderbird is restarted, the same bug occurs again

I'll attach the generated prefs.js (which looks OK to me):

# Mozilla User Preferences

/* Do not edit this file.
 *
 * If you make changes to this file while the application is running,
 * the changes will be overwritten when the application exits.
 *
 * To make a manual change to preferences, you can visit the URL about:config
 * For more information, see http://www.mozilla.org/unix/customizing.html#prefs
 */

user_pref("app.update.lastUpdateTime.addon-background-update-timer", 1142531187);
user_pref("app.update.lastUpdateTime.background-update-timer", 1142531186);
user_pref("extensions.lastAppVersion", "1.5");
user_pref("ldap_2.prefs_migrated", true);
user_pref("mail.account.account1.server", "server1");
user_pref("mail.account.account2.identities", "id1");
user_pref("mail.account.account2.server", "server2");
user_pref("mail.accountmanager.accounts", "account1,account2");
user_pref("mail.accountmanager.defaultaccount", "account2");
user_pref("mail.accountmanager.localfoldersserver", "server1");
user_pref("mail.identity.id1.doBcc", false);
user_pref("mail.identity.id1.draft_folder", "imap://none@none/Drafts");
user_pref("mail.identity.id1.drafts_folder_picker_mode", "0");
user_pref("mail.identity.id1.fcc_folder", "imap://none@none/Sent");
user_pref("mail.identity.id1.fcc_folder_picker_mode", "0");
user_pref("mail.identity.id1.fullName", "none");
user_pref("mail.identity.id1.smtpServer", "smtp1");
user_pref("mail.identity.id1.stationery_folder", "imap://none@none/Templates");
user_pref("mail.identity.id1.tmpl_folder_picker_mode", "0");
user_pref("mail.identity.id1.useremail", "none@none");
user_pref("mail.identity.id1.valid", true);
user_pref("mail.root.imap", "/home/user/.mozilla-thunderbird/l4a71msl.default/ImapMail");
user_pref("mail.root.imap-rel", "[ProfD]ImapMail");
user_pref("mail.root.none", "/home/user/.mozilla-thunderbird/l4a71msl.default/Mail");
user_pref("mail.root.none-rel", "[ProfD]Mail");
user_pref("mail.server.server1.directory", "/home/user/.mozilla-thunderbird/l4a71msl.default/Mail/Local Folders");
user_pref("mail.server.server1.directory-rel", "[ProfD]Mail/Local Folders");
user_pref("mail.server.server1.hostname", "Local Folders");
user_pref("mail.server.server1.name", "Local Folders");
user_pref("mail.server.server1.type", "none");
user_pref("mail.server.server1.userName", "nobody");
user_pref("mail.server.server2.directory", "/home/user/.mozilla-thunderbird/l4a71msl.default/ImapMail/none");
user_pref("mail.server.server2.directory-rel", "[ProfD]ImapMail/none");
user_pref("mail.server.server2.download_on_biff", true);
user_pref("mail.server.server2.hostname", "none");
user_pref("mail.server.server2.login_at_startup", true);
user_pref("mail.server.server2.max_cached_connections", 5);
user_pref("mail.server.server2.name", "none@none");
user_pref("mail.server.server2.type", "imap");
user_pref("mail.server.server2.userName", "none");
user_pref("mail.show_headers", 2);
user_pref("mail.smtp.defaultserver", "smtp1");
user_pref("mail.smtpserver.smtp1.hostname", "none");
user_pref("mail.smtpserver.smtp1.username", "none");
user_pref("mail.smtpservers", "smtp1");
user_pref("mail.startup.enabledMailCheckOnce", true);
user_pref("mailnews.quotingPrefs.version", 1);
user_pref("mailnews.ui.threadpane.version", 5);