[NTG-context] Strange ConTeXt - XeTeX problem

Hi, I'm trying to learn about using XeTeX in ConTeXt. The problem is that when I compile a file using texexec --xtx filename.tex, I get the following error message *** fontmap psfonts.map not found; texmf.cnf may be broken *** font ec-lmtt10 not found in psfonts.map or host system; will substitute Helvetica glyphs But if I just use xdv2pdf filename.tex, everything turns out perfectly. I'm wondering what the problem could be. Thanks! Sincerely, Helin -- Helin (Colin) Gai Class of 2009, Duke University Box 96332 Durham, NC 27708 Phone: 919-943-6302 helin.gai at gmail.com hg9 at duke.edu