I was having this exact problem while running MikG as well. After some research, I was able to remedy the problem by clearing the data on the Play Store app and Google Services Framework.
1. Go to menu->settings->applications->manage applications
2. Make sure you are under the "all" tab
3. Find Google Services Framework and Google Play and clear the data.
4. Stop if necessary, then reboot.
This worked for me- hope it helps.