Fatal Error: Call to a member function on null in /.../ after installing 'Custom Theme 2.0

Hello everyone,

I'm encountering a fatal error after installing a new theme and I'm hoping someone can help me pinpoint the cause. I've been troubleshooting this for a few hours with no luck.

The Issue:
After I installed and activated the 'Custom Theme 2.0' extension, my site's frontend immediately shows a fatal error instead of the homepage. The exact error is:

Fatal error: Call to a member function on null in /home/user/public_html/vqmod/vqcache/vq2-catalog_view_theme_default_template_common_header.tpl on line 125
My Setup:

OpenCart Version: 2.3.0.2

Extension Name & Version: Custom Theme 2.0, version 2.0.1

PHP Version: 7.4.30

Server Environment: Shared Hosting

Steps I've Taken:

I have disabled and re-enabled the theme multiple times.

I have cleared the OpenCart cache from the dashboard.

I have refreshed the modifications.

I even tried deleting vqcache and the theme_cache folders manually.

The error still persists. It appears to be related to vqmod and a specific line in the header template, which is likely a modification made by the new theme. Has anyone else experienced this, or could you offer some advice on how I can resolve this? I'm trying to avoid a full re-installation.

Any help would be greatly appreciated. Thank you!

Have at look at the code at the line in the file that the error is reporting. Then see if any or your vQmods are adding that code. Might give you a clue as to which ones are causing the issue.

You have a clear issue here
Fatal error: Call to a member function on null in /home/user/public_html/vqmod/vqcache/vq2-catalog_view_theme_default_template_common_header.tpl on line 125