I have been able to duplicate this error with latest version of web2py (1.91.4) and the exact wiki app in Chapter 3 of the book.
To recap, if you use the ajax search recipe described in Chapter 3, you can not have a trailing slash (bug described above). This means no arguments are can be passed to this controller. Curiously, variables (request.vars) can be passed in without having this problem. (This tells me there's something about the slash.)
