Hey bud,
I'm still a new zimbra user myself, but some of the things I would check on the remote pc would be:
Windows Firewall ? maybe it is blocking an incoming or outgoing ssl port
Remote Router ? same as the windows firewall, it might be setup to block all traffic (ipcop has a mod that does this)
Your router ? do you have all of the zimbra required ports forwarded to your internal box
Maybe you have tried these already, but if not thats where I would start. Hope it helps.
