GetDllVersion And GetFileTime

How I Can use the GetDllVersion And GetFileTime ???

What does mean Low and High? Dword?

How could I know that the file is older than another?

How could I know that the dll version is newer than another?

i couldn't figure out myself, how GetDllVersion works. i want to use it to find out which version of Nullsoft AVS is installed (winamp\plugins\vis_avs.dll). if anybody can help...