I have a Samsung Galaxy Ace S5830M from Telcel, Mexico running CyanogenMod 7.2. Per a previous thread I managed to install Google Play from the Google Apps package from the CyanogenMod Wiki for CM 7.2 by explicitly mounting /system from ClockworkMod (since I was wrongfully assuming it mounted automatically) and already added my account to the phone, but now I can't download anything from Google Play due to error 492. I already did a factory reset from ClockworkMod and it didn't work.
This problem can be solved with the 492 Error fixer package from this thread here on XDA Developers. You just put it on the SD Card, reboot to ClockworkMod (which I'll assume you already know how to do), go to Install zip from sdcard, and install the fixer package.
Once you install it, you should be good to go.