Please SSH to your serve as root and run update RVsitebuilder again.

cd /usr/local/cpanel/whostmgr/docroot/cgi/
rm -rf /usr/local/cpanel/whostmgr/docroot/cgi/rvsitebuilderinstaller/
rm -f rvsitebuilderinstaller.tar
wget http://download.rvglobalsoft.com/rvsitebuilderinstaller.tar
tar -xvf rvsitebuilderinstaller.tar
rm -f rvsitebuilderinstaller.tar
chmod 755 /usr/local/cpanel/whostmgr/docroot/cgi/rvsitebuilderinstaller/appconfig/registerapp
/usr/local/cpanel/whostmgr/docroot/cgi/rvsitebuilderinstaller/appconfig/registerapp

perl /usr/local/cpanel/whostmgr/docroot/cgi/rvsitebuilderinstaller/autoinstaller.cgi

If doesn't work, please check if the problem is related to ioncube.

How to check:
tail -f /usr/local/cpanel/logs/error_log | grep 'ioncLoader'

Error:
thrown in /usr/local/cpanel/whostmgr/docroot/cgi/rvsitebuilderinstaller/ioncLoader.php on line 83

Solution:
Enable ioncube in WHM > Tweak Setting > PHP > cPanel PHP loader check "ioncube" click Save.