Issues with Microsoft Outlook 2007 out of network

I need help, I'm a new member, and hopefully someone can give me some good directions. I currently use Microsoft outlook 2007 for my work email, this wasn't by choice, it's just what the company uses. Whenever I'm at work and plugged into our network, I can send and receive emails with no problem, but when I take my laptop away from the office I cannot send any emails. My company isn't that big and doesn's have a IT dept to talk to about this, so I have been left to figure this out on my own. I don't understand why I can receive the emails but not send them. The error message that I have received has something to do with a "STMP"? I've tried creating another email account with outlook using sbcglobal, and that has worked fine, but then any and all future emails won't be coming from my actual work email. Please help.

The SMTP is configured to only work when the computer is plugged in to the network. However, the POP or the receiving end does not need to be plugged in, because your email address is still active. The network service is configured to only work while you are connected to their network. That is the exclusive means of their email services.

I bet your on Roadrunner? I had the same issues with Verizon\Roadrunner with my HTC Windows Mobile Phone, as Dragon stated "You must be on on your cable modem to have outlook send outgoing emails.