autoexpect (manpage ) is the distribution documentation for autoexpect. Autoexpect is part of the Expect distribution. Also of interest: http://expect.nist.gov/doc/autoexpect.pdf
autoexpect is an application to create an application! Once you start autoexpect, you then perform the actions that you want to script with Expect. Once you complete, it is well worth while to exercise the script to see that it does all that you really want it to do and that all error cases are handled.
I have found that modifying the autoexpect script is pretty tough, as is trying to streamline the script and add error handling. Not impossible - just very tough for a novice scripter.