Initialize_File(Integer File# Integer Index# Integer Code# Integer Desc# Integer Type# String Type)
This initializes the data-set for finding. You MUST pass all five
parameters here. They are:
File# - main file to use
Index# - Index to use for finding
Code# - field number of the code
Desc# - field number of the code's description
Type# - field number of the constraining Type (0 if none)
Type - the constrain type value ('' = allow all records)