Cannot Send attachments

Hi I am using Avast 4.6 Home edition and there seems to be no way to send any emails with an attachment Zipped or otherwise Unless i shut down the on access protection.
Any ideas as to a fix for this.

What is your OS?
What is your email program?
What error messages are you getting to indicate the inability to send email with attachments?
How big are the attachments?

Hi i am using windows XP Home edition and outlook express for my email program The problem occurs with attachments of any type and size

Can you receive emails with attached files?
If you check Tools > Options > Security into Outlook Express, is the option for ‘virus’ checked or not?

What error messages are you getting to indicate the inability to send email with attachments? - e.g. connection timeout, wait, etc.

I’m assuming that you are able to send emails without attachments?