Well, after much trial and error, and many unfruitful Google searches, I eventually discovered the problem in a line I missed during the output when running in --verbose
mode.
The issue was resolved when I changed the file vendor/propel/propel1/generator/build.properties-example
to vendor/propel/propel1/generator/build.properies
. I also changed the versions I was using to Phing 2.4.12 and Propel 1.6.9.
Hope this helps someone in the future.