hundredths of a second

[newbie301]

How can i set the system time from a str thats "10:11:00"? I have so far
ARRAY(str) b
SYSTEMTIME st
st.wHour=val(b[1])
st.wMinute=val(b[2])
st.wSecond=val(b[3])
st.wMilliseconds=0
SetLocalTime &st
GetLocalTime &st

However, this does nothing to my clock. Nothing is changed. Is my code bad or is windows xp sp2 with mcafee blocking something?