go on your start menu, and in the start menu type in %appdata%, then click enter. You will be brought to your roaming folder. Find .techniclauncher, then go into cache and put in the minecraft_1.2.5.
.techniclauncher should be in your library, under application support here is folder link, [what ever your user name is]/library/applicationsupport/techniclauncher.... I think that is what it is