Cannot open msg attachments

[Dan4337]

I'm using Outlook 2003 and recently I cannot open msg attachments. Other attachments, word, excel, etc work fine. I have tried creating a new profile, detect and repair and re-installing Office (including Outlook 2003). I continue the get the same error – Messaging Interface Returned an Unknown Error … I can save the attached message file to my desktop and then can open. This applies for html or plain text formatted message. Any ideas would be much appreciated. Thanks, Dan