Can you ping the Guest from the Host? Note: By default Windows 7 blocks ICMP Echo Requests (ping)! 
What is the state of the Guest OSes Firewall? If need be temporarily disable it for testing purposes.
What software are you using in the Guest OS to provide the Web Service and what Port is is configured to use?
What is the IP Address you're using to access the Guest? Also... To help figure out what is what, the best way to provide comprehensive diagnostic information is to use the "Collect Support Information" command from the VMware Fusion (menu bar)> Help > Collect Support Information and then attach the .tgz file it created on your Desktop to a reply post. Or at the very least provide Guest OS configuration details and IP info for both Host and Guest.