"error PRJ0019"-How can I resolve this?

[codeboss]

I am trying to compile a Qt project using VS 2008. This a open source project. I downloaded it from internet. In the project building instruction manual it is suggested to add the path/to/Qt in the environment variable as QTDIR. I have done that. When I try to build the project sln file. It shows this error.

@Performing Custom Build Step
The system cannot find the path specified.
Project : error PRJ0019: A tool returned an error code from "Performing Custom Build Step"@

I am using Qt Quick. I have specified the QTDIR value as F:\QtSDK\QtCreator\bin.
I also tried with F:\QtSDK

There are also these bin folders in the QtSDK folders.

@F:\QtSDK\mingw\bin
F:\QtSDK\QtCreator\bin
F:\QtSDK\Desktop\Qt\4.7.2\msvc2008\bin
F:\QtSDK\Desktop\Qt\4.7.2\mingw\bin
@

What should I do to resolve this error?