You are probably converting numerics to alphas without specifying a leading zero format.
[pre]
data _null_;
DT='15JAN2009'd;
* explicit conversion, no leading zero format;
M=put(month(DT),2.);
D=put(day(DT),2.);
Y=put(mod(year(DT),100),2.);
X=cats(M,D,Y);
put _all_; * wrong;
* implicit conversion, no format at all;
M=month(DT);
D=day(DT);
Y=mod(year(DT),100);
X=cats(M,D,Y);
put _all_; * wrong;
* explicit conversion, with leading zero format;
M=put(month(DT),z2.);
D=put(day(DT),z2.);
Y=put(mod(year(DT),100),z2.);
X=cats(M,D,Y);
put _all_; * right!;
run;
[/pre]
But, that's only an assumption.
Help us to help you. As said above, you should always share you're code.
Cheers from Portugal.
Daniel Santos @
www.cgd.pt