newer version of the parser installed,yet get the older one itlself,hows it possible?

Hi all,

I downloaded a XML parser lib from blastwave.org...
Its the "libxml2",but i am having trouble initializing it(or so it feels)...I kind of need it badly as the OSE version of the virtualbox 1.6.2 will not install unless i have one

The version was 2.6.3...
The min requirement from virtualbox was 1.6.23
But even after an installation when i try to install virtualbox it still show me that i need a higher version of libxml2.
I am very sure that i have downloaded the higher version,reason being that the download link states its a ver 2.6.3
So how do i counter this?

Is there a way to check the version of my newly installed parser?

Thanks