From the attached error seems, that this is exactly the problem reported in this thread.
Could you restart the application and try to upload again. Then, if you still get the error, please execute the SQL script from this thread. This should upgrade the database.
However, did you said that this was working at some moment? If this is the case, maybe the database has been downgraded by another site with older version of Sitefinity.
The above could hopefully fix the problem, but as I mentioned before, every access to the database from a site with Sitefinity version prior to 4.2 could downgrade the database and bring this error again. So, you have to make sure, that only this site is connected to this database. I am suggesting you to rename (or restore with different name) the database and modify the connection string to use the new name.
Please, do let us know how it goes.
the Telerik team
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