I am getting the following error while I try to create a new application or a new farm.

"Unexpected exception in javascript:Badly formed JSON string: '
\nFatal error: Class \'HttpRequest\' not found in /var/scalr/app/src/
LibWebta/library/NET/API/AWS/class.AmazonS3.php on line 454
\n'"

Solution:
pecl_http php extension is missing on your system.

So start here to resolve the issue...
# apt-get install libcurl4-openssl-dev
Make sure that curl is installed then procees again
# pecl install pecl_http

add extension=http.so in /etc/php5/apache2/php.ini & /etc/php5/cli/php.ini & "copy the http.so file to the php5 lib folder "