qmake failed when building a self-signed Smart Installer package

I've installed qt creator(version 1.3.83) and wrote a simple application named 'testqt.sis'.
The 'testqt.sis' can run in a nokia6120 phone whitch has installed 'qt_installer.sis', but can't run in a phone without qt environment. So I want to package the application with Nokia Smart Installer.

I downloaded smartinstaller.sis and copied it to the directory where my application is, and follow the steps in the pdf 'Nokia Smart Installer for Symbian Developer's Guide', '2.4 Building a self-signed Smart Installer package'.

I inputed the qmake in the application's directory, it faild:

[COLOR="SlateGray"]D:\txp\top\testqt>qmake
Could not retrieve HKEY_LOCAL_MACHINE\Software\Symbian\EPOC SDKs setting
Failed to determine epoc root.
Either set EPOCROOT or EPOCDEVICE environment variable to a valid value, or prov
ide a default Symbian device.
[/COLOR]

What can I do? What does the register key mean? How to set EPOCROOT or EPOCDEVICE environment variable?

It's OK now.

I set the variable by:

set EPOCROOT=d:\nokiaqtsdk\Symbian\SDK\epoc32

and it worked successfully.