perhaps you could quote the error message verbatim.

What you are saying sounds like you are opening the attachments, not attaching them. Is there a double click in this process somewhere?

I am having a similar problem. I was able to attach .jpg files to outgoing email until yesterday afternoon. Now I get the following message " ...could not be opened, because the associated helper application does not exist. Change the association in your preferences" whether attaching from my PC or phone. Not double tapping. I have discovered when email sent to me with .jpg attachment, I am receiving it as a .dat file. I am old school (pre computers) so patience in helping me navigate to follow instructions would be appreciated.

Thank you