That error actually means the database of Picasa is corrupted and broken. You will have to rebuild it properly before you can use it again.
Go to Windows + R and type %LocalAppData%\Google\
. You'll have additional folders inside Picasa, just locate the db3 folder and delete everything except the following files:
- scanlist.txt
- thumbindex.db
- thumbs_index.db
Launch Picasa and wait for it to re-index the files. It could take 2 hours for 10.000 pictures.