make sure to include the logo URL path in the template as an absolute path (including the site's root)

Thanks, problem fixed.

After putting the absolute path of logo, eg. , I can see the see the logo online - front and back end. However, now the logo disappears from the pdf file (images not readable or empty). I switched back to default template, this problem still existed.

Please, make sure that the PHP directive "allow_url_fopen" is enabled in your server.

Is there a resolution to this? I have PHP directive "allow_url_fopen" is enabled on my server and I have put in the absolute path but I still can't see the logo in the PDF.

(I'm running v1.4.9 but don't want to purchase an upgrade if the system has bugs and if I can expect to get less that 1 year of bug free use.)

the solution is to have allow_url_fopen enabled and to use absolute paths, just like you described... This is required in order for DomPDF to be able to render the image.
Any other user that had this problem solved it by doing this... it's not a bug, it's a requirement of the system that the PDF library needs in order to work.

If you're having this problem after having done this, there must be some other server config that is causing it...