Sharing a internet connection Getting error 123!?

[phiber_optikuk]

Hello all, I am trying to share my internet connection but i keep getting the same error - Error 123 the filename, Directory name or volume label syntax is incorrect. This happens everytime i goto network connections right click my connection, properties, advanced tab then ticking the box Allow other network users to use this connection. I have also noticed that in services the windows firewall/internet connection sharing (ICS) service is not started and when i select the option to start the service i get the same error!

Thanks for any help people can offer!