Home Made Fudge not Hardening?!

it's usually sweetened condensed milk, so you probably didn't have enough sugar in the mix. You really need a sugar boiling thermometer to stop it at the right temperature too (though testing a drop in ice water works, too)

Most recipes call for sweetened condensed milk, and I suspect that was part of the problem. Other factors include cooking to the right temperature (I rely on a candy thermometer instead of the cold water test) and the humidity. Too much humidity and the fudge won't set up properly. Also, if the recipe requires beating the candy by hand, did you really put some elbow grease into it and beat it until it lost that glossy appearance?