This is not really my area of expertise but as I frequently use the web mail part of domino I get into this problem from time to time.

When trying to download attachments from the web mail I get the message: Error unable to download file "some filename.doc" from whaterver.com.

Some attachments work, others do not.

This is probably a silly question but I need a solution.

Hi Tomas,
I found this technote which I think is what you are looking for. There doesn't seem to be a clear solution to the problem as it's some kind of bug that affects only 6.5.5 and should be fixed in the Domino Web Access 7 template. If that's the case for you maybe you have the possibility to upgrade the DWA template?

Otherwise there is a workaround suggested according to the technote:
You can work around the problem by forwarding the affected e-mails to yourself from within Domino Web Access. You can then open the attachment without error from the forwarded mail. Or, you can open the mail file in a Lotus Notes client to view the attachments.

HTH / Niklas

Good info!
Gives me a reason for why we should upgrade our old mail server!