Having been inspired by Doug Hennig's article in FoxTalk Feb 2000 where he describes how to use the MSMapiMessages and MSMapiSession controls (in MSMAPI32.OCX) I came across a problem when trying to attach a file to my e-mail.
I've e-mailed Doug directly and he advised me to ask here.

I know there's a problem with trying to attach multiple files (as described in Technet article Q181899) - but I'm, only trying to attach one file and, anyway, Doug's code that I'm trying does increment the attachment position property.

I set the MapiMessages attachment properties (using Doug's code in SFMapi) but when the code in SFMapi.Send calls the oMapiMessage.Send method the following error is retuned in aerrorinfo[]
aerrorinfo[1] 1429
aerrorinfo[2] "OLE IDispatch exception error code 0 from MapiMessages: Unspecified Failure has occurred"
aerrorinfo[3] "Unspecified Failure has occurred"
aerrorinfo[4] "MSMapi.Messages"
aerrorinfo[5] Mapi98.CHM
aerrorinfo[6] 32002
aerrorinfo[7] 0
and the e-mail dialog doesn't come up.

I specify the full pathname for the file I'm attaching and have checked that it's not in use by another app when I try the .Send().

If I don't specify an attachment at all then the code works fine.

Any help gratefully accepted.

Anna