[plt-scheme] λ doesn't work in HtDP languages

[Todd O'Bryan]

The subject says it all. We just did lambda today, and the lambda you
insert from the menu doesn't work for Intermediate Student with lambda
or Advanced Student. You get:

λ: name is not defined, not a parameter, and not a primitive name

This is with version 4.1.5.4-svn13apr2009 (as well as with the
released 4.1.4 and 4.1.5).

Such a letdown... :-(

Todd