WinNT provider for adsi

I want to get and put user account policy
like :
MaxPasswordAge
MinPasswordAge

i use following code

hr = ADsOpenObject(L"WinNT://Adserver", L"Administrator",L"Stellar@123",ADS_READONLY_SERVER,IID_IADs, (void**) &pUsr);
long l=0;
hr = ADsGetObject(L"WinNT://Adserver/Administrator,user", IID_IADsUser, (void**) &pUser);

hr = pUser->Get(L"MaxPasswordAge", &var );
l=var.lVal;
l=l / (60 * 60 * 24);
VariantClear(&var);
hr = pUser->Get(L"MinPasswordAge", &var );

l=var.lVal;
l=l / (60 * 60 * 24);
VariantClear(&var);

i get value successfully but when i try to put

as:
V_VT(&var)=VT_I4;
var.lVal=0x16;
hr =pUser->Put(L"MinPasswordAge",var)

I got error

please tell me how can i put user account attributes.

thanks

vipin