He is mentioned in several books about juju music, and he features on the wonderful CD "Awon Ojise Olorun -Popular Music in Yorubaland 1931-1952". But nevertheless Theophilus Iwalokun seems doomed to be one of the many forgotten heroes of African music.
I am assuming that this lp is from the latter part of his career. But that's about all I can tell you about this artist.
Maybe someone knows more?
EDIT August 17, 2010: the link has been renewed!
César Castro y sus Nuevos Éxitos Caliente 1973
9 hours ago