Content / fields of newly created single don't show up After a fresh install of Craft on my localhost, two problems occur:

1) The modal window to upgrade Craft only says "An unknown error occured."

2) Newly created singles are not editable, the edit pane stays empty with no input fields at all.

I looked into craft.log and there seems to be an issue with CHttpRequest.php, but I can't say if this is a local config problem or if it's a bug:

******************************************************************************************************
2015/02/25 13:08:35 [error] [php] Cannot modify header information - headers already sent (/Users/me/Sites/test-dev-craft/app/framework/web/CHttpRequest.php:1392)
Stack trace:
#0 /Users/me/Sites/test-dev-craft/app/framework/web/CHttpRequest.php(1329): Craft\CookieCollection-&gt;remove()
#1 /Users/me/Sites/test-dev-craft/app/services/UserSessionService.php(1170): Craft\CookieCollection-&gt;add()
#2 /Users/me/Sites/test-dev-craft/app/framework/web/auth/CWebUser.php(203): Craft\UserSessionService-&gt;renewCookie()
#3 /Users/me/Sites/test-dev-craft/app/services/UserSessionService.php(91): Craft\UserSessionService-&gt;init()
#4 /Users/me/Sites/test-dev-craft/app/framework/base/CModule.php(387): Craft\UserSessionService-&gt;init()
#5 /Users/me/Sites/test-dev-craft/app/etc/web/WebApp.php(569): Craft\WebApp-&gt;getComponent()
#6 /Users/me/Sites/test-dev-craft/app/framework/base/CModule.php(103): Craft\WebApp-&gt;getComponent()
#7 /Users/me/Sites/test-dev-craft/app/etc/web/WebApp.php(160): Craft\WebApp-&gt;__get()
#8 /Users/me/Sites/test-dev-craft/app/framework/base/CApplication.php(180): Craft\WebApp-&gt;processRequest()
#9 /Users/me/Sites/test-dev-craft/app/index.php(62): Craft\WebApp-&gt;run()
#10 /Users/me/Sites/test.dev/index.php(19): require_once()
REQUEST_URI=/test.dev/index.php/admin/actions/tasks/getRunningTaskInfo


This is my local setup:


Mac OS X 10.10.2
Apache/2.2.29 (Unix) DAV/2 mod_fastcgi/2.4.6 mod_ssl/2.2.29 OpenSSL/1.0.2
PHP Version 5.6.5
MySQL 5.6.22 - Homebrew


Any help would be highly appreciated!
I was having a similar issue and found a solution that worked for my setup:  https://craftcms.stackexchange.com/a/9016/831