At one point in time, you have received a message stating that LW detected a corruption in a file & asked you whether to continue or not. You have ticked "no" & ticked always use that answer. What you need to do is go to LW's menu bar, Tools>Options>View>Popups & tick the option to Revert to Default.

Now, why are you receiving this message so often? It could be a firewire not properly configured or an aggressive anti-virus or other utility, etc. Or the files you are choosing are corrupt in the beginning. BTW a corruption can be as small as the id3 tag of an mp3 has changed since you 1st started downlding it so it doesn't agree with the original hash of the file you started to downld. The most recent LW betas have stopped this happening with such small corruptions due to id3 tags & descriptions of videos. AFAIK

Do you see a brick wall in front of the blue world icon at the bottom of LW's interface?

See T3 Spammers; mp3 Bit-Rates Versus File Sizes as that might be one reason.

BTW to resume your files, go to LW's Library window, select incomplete folder, select the files corrupted & press Resume*. Another option is to research the file topic & rechoose to downld (**** but initially cancel the file from the downld window!)