Pop, have you tried to logon and send using another browser such as Firefox?
I have had problems in the past with attachments and Gmail but switching
browsers solved it for me. Clearing the cache on your existing browser can
cure many Gmail ills as well.
Specific to the 008 error is a troubleshooter
here.
I don't know what good it might do but there is a general online Gmail troubleshooter available
here.
Good Luck!