You need to upgrade to at least CS5. ACR is version specific and your camera came out long after CS4.
What Conroy said. Convert the 60D Raw files to DNGs then edit the DNGs in CS4.
A DNG workflow primer
To edit 60D Raw files, you need at least ACR (Adobe Camera Raw) 6.2. ACR is a plugin for Photoshop which Adobe must continually update on a camera by camera basis.
CS5 was the first version to support ACR 6.2
If you really want to edit Raw files, you would now be required to join the Creative Cloud since CS4 is no longer eligible to upgrade to CS6 or any version thereafter.