  We present a new approach to construction of protocols which are proof
against communication errors. The construction is based on a generalization of
the well known Ulam's game. We show equivalence between winning strategies in
this game and robust protocols for multi-party computation. We do not give any
complete theory. We want rather to describe a new fresh idea. We use a tree
code defined by Schulman. The tree code is the most important part of the
interactive version of Shannon's Coding Theorem proved by Schulman. He uses
probabilistic argument for the existence of a tree code without giving any
effective construction. We show another proof yielding a randomized
construction which in contrary to his proof almost surely gives a good code.
Moreover our construction uses much smaller alphabet.
