A firewall normally doesn't block attachments. If you have Outlook or
Outlook Express, it is more likely that your email program is set to
deny the saving/opening of attachments. Look under Tools>Security.
If this is not your issue, then please post back after going to this
link to see what information to include in a newsgroup post:
Addendum - I just noticed your subject line of "webcam". That means my
advice about email attachments doesn't apply. Next time put something
about the problem in the body of your post.
Then come back with all the missing details (what webcam? what firewall?
what Service Pack level XP? what antivirus? what Internet connection?
etc.) and someone will help you.