Hi!
Generally such problem may ocur when something was externally changed in DBeaver installation. Can't say how it can happen, but probably by some manual Eclipse installation or DBeaver reinstallation without removing previous version.
Basic solution of such problem is to completely reinstall DBeaver (database configurations won't be lost). If you use portable version of DBeaver (from zip archive) then you need to completely remove previous version before extracting files.
If problem won't be fixed by reinstall then could you send me (by email or attach in forum message) complete log file?
Thanks for report!