Running Tomcat as a NT Service

[transparent]

I install Tomcat 4.1.18 as a NT Service so that I don't need startup and showdown it manually. But I found a problem: if I startup tomcat as NT Service, I can access my local hard drive, but I can't access hard drive on the other's computer (I already mapped the shared folders on the other's computer to my computer). But if I startup tomcat using startup.bat, everything is fine. I don't know it relates with some security policy or environment viriables set by startup.bat. I use Windows 2000 server and I already set JAVA_HOME and CATALINA_HOME. Is there anyone can give me some help, thanks a million in advance.
(so sorry that I can't input Chinese character because of my OS.)