Jan,
I have looked at the Central Scotland FHS index to Alloa burials, and I am afraid there is no reference to any John Erskine. This index relates to names appearing in the Church records for the parish (for instance for the hire of the mortcloth), and the number of entries is quite small.
It could still be that there is a gravestone record in the M.I.'s which maddymoss is going to look at for you.
David.