Word (Standard 2010) Issues with printing docs with both envelopes & 8.5x11 letters

Every time I try to print a word document that has an envelope and regular letter at the same time, my Xerox machine prints the envelope but then says I must load the 8.5x11 paper into the same bypass tray the envelopes load from. What it SHOULD be doing is printing the envelopes from the bypass tray and then printing the 8.5x11s from the normal letterhead tray. I cannot find any reason this is happening from my xerox/word/computer/printer settings--everything looks normal. No one else in my office has this problem--the Xerox talks to their machines just fine and prints envelopes from the bypass tray and letters from the letter tray with absolutely no issue. A large part of my job is printing thank you letters to donors, so this is really frustrating me!

I am working with Word Standard 2010.

My computer is Windows 7 Professional.

My printer is Xerox C7030.