EzPCB prefers zipped gerber 274x and excellon file format. If your pcb file is not in this format please convert it into gerber274x.

The only exception is protel. Customers can send us protel PCB file without convert into gerbers.

Eagle users no need to be sad, it's a minute's work from Eagle *.brd to Gerber274x. Here's a link telling you how to do it:

http://www.interq.or.jp/japan/se-inoue/e_eagle44.htm

Eagle users can gererate the gerber files in one minute by the instructions in this page.