DownloadManager is querying request.list located in diffrent location.
<User Home>/AppData/Local/VirtualStore/Program Files/Java/jre6/lib/bundles/requested.list

DownloadManager checks this first , I think DownloadManager should look only into <jre>/lib/bunldes/request.list , If not as part of un-installation we should remove this file.
Otherwise even with out specifying setAdditionaBundles() DownloadManager will try to download bundles. I will file a bug on this.
I am getting the IOException because of this and I am not getting this. Even the NumberFormatException while downloading rmi bundle ( 6667677 ) again is due to this.