Archived:Download Manager API - download cannot be continued (Known Issue)
If an application is using the Download Manager API to download DRM-protected or OMA content, exits the application (and the download) for a while, then starts the application again and tries to resume the download, this will fail.
This feature is not supported by the Download Manager. Resuming a download is allowed only for non-DRM and non-OMA downloads. The download engine is designed so that any DRM/OMA content download is deleted if the client application is closed, thus re-starting your application and the CurrentDownloads() returning a zero value is correct behavior for DRM and OMA downloads that were exited.