Autoselect not autoselecting

My office recenly installed a new Xerox Phaser 5550 printer, and odd behavior followed.
From all programs except Acrobat, printing is fine. The printer selects the appropriate paper, and all is well.
When printing from Acrobat, the paper used is whatever was selected last in the File/Page Setup dialog box. The print dialog box selection for "Choose paper source by PDF page size" is selected, but has no effect. The print preview appears correctly, but the actual print will come out different.
I print both landscape and portrait, in both 8-1/2 x 11 and 11 x 14 sizes.
The previous printer was an HP, anad it printed fine. The problem came with the new Xerox, but only with Acrobat, nothing else.

Ideas?

Thanks