Problems printing with glabels

I'm having a peculiar problem with glabels. I don't know yet if it is a problem with the app, or if it is a problem with the printing system.

I'm using Ubuntu linux, 6.06; kernel 2.6.15-25-386 #1 PREEMPT with Cups 1.2.0 and the Gutenprint driver for my Epson Stylus Photo 890. But I had this problem also with Mandriva a couple of months ago.

I set up a template for Avery 05453 self adhesive labels. This format has two labels per sheet, no space between or around labels, on a sheet 102mm wide by 152mm high.

So I set up this template, and placed my text. Did a print preview, and everything looked OK.

But when I tried to print to the label, the text was offset towards the bottom right, as if printing in the centre of what would be a US Letter format sheet (which is the default paper size for the printer).

So, thinking it was a problem with the default paper size not being over-ridden by the output from glabels, I printed first to a PDF file, to check. This gave me well formatted output, but printing this even with the paper set to a custom size of 102mm wide by 152mm high, the print was still offset.

I'm perplexed, and googling hasn't turned up any similar problems.

Any ideas how I can at least isolate the problem to be either the software or the printing system?

Beef.