Digital BW, The Print

Trying to print a 103/4 " by 151/2 " print on Super A3 paper with my 1280 
and UT inks ---This image prints perfectly with smaller proofs but stops 2/3 
of the way through on the bigger paper.  The print is to be auctioned at a 
benefit over the weekend and I'm desparate to figure out this problem.  Any 
help appreciated.

Thanks.

Barbara