Mail merge fails after transfer to Windows 7

[Derby Loco]

Hi - I have used the mail merge function in Word 2003 successfully to print address labels on 8.5" x 12" fanfold paper with an Epson LX-400 printer for a long time. I have now got a new computer with Windows 7 and Word 2010 but am having difficulty with the label printing.
I installed the recomended printer driver for the LX-400 which is listed as LX Series 1 (80) and I copied the word template file and the related .mdb files over to the new machine.
Everything seems to work with the merge running and the Preview within Office 2010 looking correct but when I actually print the the labels I get an error message that "The margins of section 1 are outside the printable area of the page". Also a print preview shows the top of the first label cut off. If I ignore the error and print the first line is cut-off and the same happens at each page break. (If I click fix top and bottom margins get added.)
The page top and bottom margins are set to 0 and the printer to tractor feed but it seems that the document is being treated as if each page had a top and bottom margin.
What am I missing and appologies if this has been asked before. I have tried to search for an answer but not found one.