How to install on Win7 x64:
 

1.       Extract it to for example c:\lame

2.       Run cmd with admin rights (ctrl+shift+return)

3.       cd %windir%\SysWOW64

4.       rundll32 setupapi.dll,InstallHinfSection DefaultInstall 0 C:\lame\LameACM.inf

(Thanks to Markus Stein.)