First you are matching the Calendar by DealerID as KeyField - to create an Calendar you should use the DATEFIELD as KeyField,
Second I think you having dates in your source data which aren't format correct try to use date#() instead of date() to cast a right formated date by Loading it.
Somthing like this:
Dealer1:
LOAD ......
date#(DealerInvoiceDate,'DD-MM-YYYY') as DealerInvoiceDateKey
.......;
Tmp_MinMaxDate:
Replace Load
Min(%DealerInvoiceDateKey) As MinDate,
Max(%DealerInvoiceDateKey) As MaxDate
Resident Dealer1;
/******************** Set Vars *******************/
Let vMinDate = Peek('MinDate', 0, 'MinMaxDate') - 1;
Let vMaxDate = Peek('MaxDate', 0, 'MinMaxDate');
Drop Table Tmp_MinMaxDate;
Datefield:
Replace Load date($(vMinDate)+Iterno()-1) As Datefield
Autogenerate 1
While $(vMinDate)+Iterno()-1 <= $(vMaxDate);
Calendar:
Replace Load *,
Datefield As %DealerInvoiceDateKey,
Datefield As MyDate,
Year(Datefield) As Year,
Year2date(Datefield)*-1 As YTDcurYear,
Year2date(Datefield,-1)*-1 As YTDlastYear,
Month(Datefield) As Monat,
date(monthstart(Datefield), 'MMM-YYYY') As curMonth,
'Q' & Ceil(Month(Datefield) / 3) As Quarter,
week(Datefield) As Week,
week(Datefield) & '-' & Year(Datefield) As curWeek,
