>Supose today is 10/02/01.
>xdate = DATE() && Todays date
>1)
>? INLIST(ALLTRIM(STR(MONTH(xdate))),"1","2") && If Jan or feb (Returns .T. <<== ERROR)
>* Here I expect .F.

You've already got an answer to this, but... why not just
?inlist(month(xdate),1,2)