After upgrade to 12.0.3 I got "TCPDF_PARSER ERROR: Empty PDF data."

I am using crabe to create PDF invoices with a modification merged pdf signature while creating a document.
After upgrade to version 12.0.3 (from 11.x) I am having a problem with “crabe” module. The file podpis_jernej1.pdf is holding a scan of my signature, looks that after upgrade the file is being searched at different location as before the upgrade.

Warning: file_get_contents(/podpis_jernej1.pdf): failed to open stream: No such file or directory in /var/www/html/includes/tcpdi/tcpdi.php on line 120

Any ideas?

Maybe you can try a clean install. Or debug where the code expects your file to be located and fix it.