Hello Petra Kalbreyer-von der Heyde,
Thank you for reporting this issue, and I apologize for any inconvenience this update to the Shaper_onepage template has caused. I also apologize for the delay in responding due to the weekend.
To help me investigate the "HelixUltimateFeaturePreloader" error, would you be willing to grant me temporary administrative access to your site? This will allow me to examine the problem directly and implement a solution.
Before providing credentials, I strongly advise creating a complete backup of your website to ensure the safety of your data.
Looking forward to your response.
Best regards