Thanks you two.
That what I thought about the .doc extension, but it was attached. Anyway...
I tried something simple that has worked for some reason: opened the document, saved it with a new name on to the desktop (not in my documents folder where the other one is) and presto - it attaches. I have only sent it to myself, but here shouldn't be a problem ...
Thanks for the help. Will report back if it continues to asplode.