The next three errors are caused by trying to define a variable more than once. The solution is simple: delete the offending lines.
Program schoolSBA;
{This program was written by Michael Jarvis, a student of the Saint Mary's Academy.}
uses crt, dos;
Type
Memberdatabase = record
Member_ID : string[10];
Member_Name : String[30];
Member_TicketPayment : integer;
Advert : string;
end;
MemberDatabaseDDC = record {declaration of record}
Member_ID : string[10];
Member_Name : String[30];
Member_TicketPayment : integer;
Advert : string;
end;
MemberDatabaseDPI=record
Member_ID : string[10];
Member_Name : String[30];
Member_TicketPayment : integer;
end;
MemberDatabaseDSGO = record
Member_ID : string[10];
Member_Name : String[30];
Member_TicketPayment : integer;
end;
Databasefiletype = file of Memberdatabase;
var
DDCFILE,
DPIfile,
DSGOfile : Databasefiletype;
DDCfile : file of MemberDatabaseDDC;
RecDDC: MemberDatabaseDDC; {variable for DDC record}
DPIfile: file of MemberDatabaseDPI;
RecDPI: MemberDatabaseDPI;{variable for DPI record}
DSGOfile : file of MemberDatabaseDSGO;
RecDSGO :MemberDatabaseDSGO; {variable for DSGO record}
Choice, count,i: integer;