I have created an update for fixing the market compatibility. I don't have a device to try it on but I think it should work on S7100A and B. It only adds xmls in the /etc/permissions/ so you can copy the files manually too.
Please try it and report back.
Download the update.zip
Copy it to the sdcard
Go to recovery and install update from sdcard
Delete Google Play's cache in Settings->Applications->Google Play
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