Installation Problem:

|| Fatal error: Uncaught Error: Function name must be a string in /var/www/html/magento/app/code/core/Mage/Core/Model/Layout.php:555

$out .= $this->getBlock($callback[0])->$callback[1]();

to

$out .= $this->getBlock($callback[0])->{$callback[1]}();

|| Maximum execution time of 30 seconds exceeded in magento installation.

/* solve */
go to xampp/php/php.ini and search by 

max_execution_time=30  replace to 600
max_input_time=60      replace to 600
memory_limit=128M      replace to 1000m

|| PHP extension soap must be loaded

I edited php.ini and removed the leading semicolon ( ; ) from extension=php_soap.dll.
After restarting Apache I was able to proceed with the installation without any other issues.