This error pops up saying database out of date.
* find the tracking.db3 file in your appdata folder (for windows 7 its C:\programData\Rosetta Stone\tracking.db3 (hidden folder) and rename it to tracking.db3.bak
* Restart the pc
* launch rosetta stone (all your progress has been lost now)
* close the rosetta stone application
* rename tracking.db3.bak to tracking.db3
* Launch the application again and here you go, you can use it again
For error code 2123:
Solved by simply reboot, and reboot, and reboot, until it is fixed.
BTW, adding a line in the file dynamicStoredPaths.xml, next to tracking.db3, may help:
Line added to second last line of file, before </installerDefaults>.