Hello,
You can try without a PDF as template, it will create an empty PDF document.
The template implicates other kind of PHP library and maybe the PDF do have some special features enabled which make it more difficult for the library to use as a template document. PDF document can have embedded fonts, etc.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.