Steps to reproduce the issue

Expected result

Actual result

System information (as much as possible)

PHP Built On Darwin MacBook-Pro.local 14.1.0 Darwin Kernel Version 14.1.0: Mon Dec 22 23:10:38 PST 2014; root:xnu-2782.10.72~2/RELEASE_X86_64 x86_64
Database Version 5.5.38
Database Collation latin1_swedish_ci
PHP Version 5.5.14
Web Server Apache/2.2.26 (Unix) mod_fastcgi/2.4.6 mod_wsgi/3.4 Python/2.7.6 PHP/5.5.14 mod_ssl/2.2.26 OpenSSL/0.9.8zc DAV/2 mod_perl/2.0.8 Perl/v5.18.2
WebServer to PHP Interface apache2handler
Joomla! Version Joomla! 3.4.0-beta1 Beta [ Ember ] 27-January-2015 20:00 GMT
Joomla! Platform Version Joomla Platform 13.1.0 Stable [ Curiosity ] 24-Apr-2013 00:00 GMT
User Agent Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/40.0.2214.115 Safari/537.36

Additional comments

I'm getting an error 400 message when activating the Install from Web tab on localhost. I dumped the install and reinstalled again thinking it was just that instance, but got the error 400 message again.

1. downloaded J3.4 beta1 from site
2. unzipped into htdocs/j34b1 (localhost)
3. installed via web installer
4. tried to activate Install from Web tab.

Using MAMP Version 3.0.6. - Anyone else having a problem with this?

"Warning
Update: :Extension: Could not open http://appscdn.joomla.org/webapps/jedapps/webinstaller.xml

Error connecting to the server: 404"