Can't open pdf attachments in Evolution

I am running 11.4 with KDE 4.6.5 and using Evolution as my email client. I actually prefer Thunderbird but need the calendar coordination features as “everyone” else is running ms and I need to respond to meeting requests, schedule meetings, etc.

Problem is that I often receive pdf attachments and they cannot be opened while in Evolution or even if saved as a pdf to be later opened with Okular. Either way, Okular simply states 'could not open xxxxxx.pdf"

Evolution is setup to leave mail on the server so I can later download and archive in T’bird. After Evolution fails to open a file, I can immediately download to T’bird and all is fine. Can open the file from within T’bird or save as pdf and open later with Okular.

Also, files that I cannot open while in Evolution, cannot be opened when forwarded to others who are likely running Windows and using Outlook. Files forwarded with T’bird are fine when received by others.

I do not see any place in Evolution to configure attachments and cannot find any similar problems when I google.

Any suggestions?