Corrupt downld preferences are usually due to not closing LW down properly before you shutdown the comp., or the comp crashes. Though it can also happen if you jump backwards in LW versions.

I didn't realise you were refering to resuming downlds after the LW downld preferences became corrupted. Then yes, if they're corrupted then there's nothing you can do about it b/c the downld progress will have been lossed. (I thought you were refering to resuming downlds normally using the resume/find sources function, not the resume function in the Library.) But yes you can get them to start downlding but they'll most likely start from 0% in the case of corrupted downld preferences.