After the installation of my ant in my windows 7 . In cmd i typed ant -v it\'s given the ant version but it says the following also.
Buildf
If I understand correctly, you assumed that -v is the "print version" command. Check the documentation, that is not the case -- instead ant -v is running ant build in verbose mode. So ant is trying to perform your build, based on the build.xml file, which is obviously not there.
To answer your question explicitly: there is probably nothing wrong with both the system nor ant installation.