Read remote file in windowsXp?

How do you do!
My driver is very correct by impersonating user thread in Win2000 to read
remote
file,but it appears bule screen in WindowsXp.Please tell me,why?
Source :
SeCreateClientSecurity(
PsGetCurrentThread(),
&QualityOfService,
FALSE,
pSecurityContext);

Is there other ways of reading remote file in Xp?