You may download updates if you want to upgrade your version of WinMLS2000 without downloading the full version. The updates may not include all files, such as setup files. The file TeeChart5.ocx is needed only if you if your version is from year 2001. It should replace your old TeeChart5.ocx found in your system directory and it allows for displaying all the minor gridlines when plotting the frequency response on a logarithmic x-axis.