Hi,
Don't know if this will help, but we had the same error, but it was indicating line 988 for us...

Anyway, during install I made the mistake of renaming the file \includes\modules\pages\checkout_confirmation\header_php.php to header_php_old.php to preserve it in case I decided to revert back and uninstall the mod.

I shouldn't have. Turns out that was the problem. I changed the name to old_header_php.php and everything works great now...

Again, don't know if it will do any good, but it's worth sharing in case it helps.