Error while changing Posting Date in Purchase Invoice "No. Series Code does Not Exist"

Dear ,

I am getting an error after i change the posting date of Purchase Invoice

“No. Series Code does Not Exist”

I ran the debugger it breaks at on validate of Posting date .

TestNoSeriesDate(

“Posting No.”,“Posting No. Series”,

FIELDCAPTION(“Posting No.”),FIELDCAPTION(“Posting No. Series”));

TestNoSeriesDate(

“Prepayment No.”,“Prepayment No. Series”,

FIELDCAPTION(“Prepayment No.”),FIELDCAPTION(“Prepayment No. Series”));

TestNoSeriesDate(

“Prepmt. Cr. Memo No.”,“Prepmt. Cr. Memo No. Series”,

FIELDCAPTION(“Prepmt. Cr. Memo No.”),FIELDCAPTION(“Prepmt. Cr. Memo No. Series”));

NoSeries.GET(“No. Series”);

NoseriesMgnt.SetNoSeriesLineFilter(NoSeriesLine,“No. Series”,TODAY);

IF NoSeries.“Date Order” AND (“Posting Date” < NoSeriesLine.“Last Date Used”) THEN

ERROR(

Text0006,

NoSeries.Code,NoSeriesLine.“Last Date Used”);

VALIDATE(“Document Date”,“Posting Date”);

IF (“Document Type” IN [“Document Type”::Invoice,“Document Type”::“Credit Memo”]) AND

NOT (“Posting Date” = xRec.“Posting Date”)

THEN

PriceMessageIfPurchLinesExist(FIELDCAPTION(“Posting Date”));

IF “Currency Code” <> ‘’ THEN BEGIN

UpdateCurrencyFactor;

IF “Currency Factor” <> xRec.“Currency Factor” THEN

ConfirmUpdateCurrencyFactor;

END;

IF PurchLinesExist THEN

JobUpdatePurchLines;

UpdatePurchLines(FIELDCAPTION(“Posting Date”));

thanks If any one can suggest the reason for error…