Song is Blues in Hoss' Flat by the Count Basie Orchestra. This is the same version as the movie, except in STEREO-some remixing for instrument clarity and separation. It is from the 1958 "Chairman of The Board" album, and "The Errand Boy" is from 1961.
Eddie Jones - Bass
Freddie Green - Guitar
Sonny Payne - Drums
Count Basie - Piano
Joe Newman on the trumpet solo at the end.