Please advise, which are you using:

• Joomla version - 3.10 (or 3.9.x) or 4.x?
• PHP version - 7.4, 8.0.x,8.1.x, 8.2.x?

Without knowing the details of your server or joomla environment etc, just guessing that it's your PHP version and some incompatibility between PHP and your version of Helix Ultimate.

Helix Ultimate was most recently updated August 2022. PHP 8.2.0 (stable) was released in December 2022 so it's possible the template doesn't work under PHP 8.2.

Note that XAMPP ships with the latest PHP version (a single version) but provides several downloads of the different PHP versions with XAMPP; I don't know where you get the reference to XAMPP v 3.3.0 from?.

If you're using XAMPP (the PHP 8.2 install) then perhaps there's something in SPPB not quite compatible with PHP 8.2 (or with Helix Ultimate template).

Refer to https://www.apachefriends.org/download.html which shows downloads for XAMPP with PHP 8.0/8.1/8.2.

My suggestion for solutions:

• Install XAMPP with an earlier PHP 8 version such as 8.0 (for Joomla 3.10 and earlier) or 8.1 for Joomla 4 and later; OR
• Install WAMPServer which comes with several PHP versions out of the box, and allows you to add more PHP versions (as well as the other server elements like Apache, MySqL, MariaDB and PHPMyAdmin), as modules which can be installed without affecting the sites you're working on within the localhost environment.

Note you will need to backup your website, and restore it in the new version of XAMPP along with a new database etc. (WAMPServer avoids all this extra work as it simply allows you to select the PHP version on the fly).