[XeTeX] "I can't find the format file `xetex.fmt'!"

[Stephen Moye]

It has been a long day. I just installed the latest update of gwTeX,  
reinstalled XeTeX, and now I am confronted with this error message:

This is XeTeX, Version 3.141592-2.2-0.95 (Web2C 7.5.3)
kpathsea: Running mktexfmt xetex.fmt
fmtutil: format directory `/Users/smoye/Library/texmf/web2c' is not  
writable.
I can't find the format file `xetex.fmt'!
tcsh: rm: No match.

What am I doing wrong?

Thanks.

SGM