.dmg file won't open, invalid checksum

Hi there -

I'm downloading the CS6 Master Collection trial via the Adobe Download Assistant onto a Mac running OS 10.7.4. When I try to open the .dmg file, I get the warning:

The following disk images couldn't be opened

MasterCollection_CS6_LS16.dmg, invalid checksum

If this helps, the download bar in the Assistant says "Extracting... this may take a while." It's been like that for about three hours.

Do I need to re-download? It took ~24hrs, so if I don't have to, I'd rather not.

Thanks!