3124266 is a very old patch and has been replaced by newer cumulative updates. That being said, I was able to download the patch from View > Patches a few moments ago: (didn't want to wait for the full download)
I would highly suggest scanning the target with a Security Patch template and install the CSWU-### patch that shows missing. That would be the latest applicable to the target machine.
Let me know if you have any questions.
I'm going to see what I can do about scanning the machine. In the mean time, at least you showed me how to be able to download a patch like this. Thank you so much!