On Unix/Linux and Win32+CygWin, copy fixdbslide into /usr/local/bin or $HOME/bin. Make the file executable with chmod +x fixdbslide.
On plain ol' Windows without bash and sed this script is completely useless, so you don't need to install it unless you want to admire its ingenuity. You should try and find some free- or shareware search-and-replace tool instead.