Tell me, Schemer!

Most of the algorithmic problems in Viivi are trivial and can be fixed just after they are reported to the author.
A few essential problems, however, go above the author's understanding.
(Unfortunately, the author is not a Real Schemer, but just one of Little Schemers.)
They are listed here and the author would like to ask the Schemers to show him the ways for the solutions.

List of Unsolved Problems

1. [Resolved] About the Scope of the Tail-Recursive Call with an Argument of a Lambda Call