Hi I have some bad download item in transfer list.
Now, I fix it. If you want to delete it, follow below.

open X Terminal
sqlite3 /home/user/cuteTube-QML/cuteTube-QML.sqlite
sqlite> .database
seq name file
--- --------------- ----------------------------------------------------------
0 main /home/user/cuteTube-QML/cuteTube-QML.sqlite
sqlite> .tables
downloads
sqlite> select * from downloads;
|||0|0|0|0|0|0
|||0|0|0|0|0|0
|||0|0|0|0|0|0
|||0|0|0|0|0|0
|||0|0|0|0|0|0
|||0|0|0|0|0|0
|||0|0|0|0|0|0
|||0|0|0|0|0|0
sqlite> .schema
CREATE TABLE downloads (videoId TEXT UNIQUE, title TEXT, thumbnail TEXT, convertToAudio INTEGER, youtube INTEGER, dailymotion INTEGER, youporn INTEGER, xvideos INTEGER, xhamster INTEGER);
sqlite> .explain
sqlite> select * from downloads where dailymotion=0;
vide title thum conv yout dailymotion yo xvideos xhamster
---- ------------- ---- ---- ---- ------------- -- ------------- ----------
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
sqlite> delete from downloads where dailymotion=0;
sqlite> select * from downloads;
sqlite>.quit


So that fail download items are discard.