Hi,
It looks like you installed the code (it's running /usr/bin/astrometry-engine), so it's going to look for the astrometry.cfg file first in /usr/etc/astrometry.cfg, then /etc/astrometry.cfg. It's not going to look in your current directory or ./etc/astrometry.cfg, unless you tell it which config file to read, using
solve-field --config etc/astrometry.cfg
You can add the "-v" flag to solve-field to get "verbose" output, including a line like this that tells you which config file it's reading:
Solving...
Running:
/usr/local/bin/astrometry-engine --verbose /Users/dstn/astrometry/demo/apod4.axy
Using config file "/usr/local/bin/../etc/astrometry.cfg"
cheers,
--dustin