Unable to share computer’s internet connection (ICS) problem

Unable to share computer’s internet connection with an error “an error occurred while internet connection sharing was being enabled.”

There is following methods:
Method 1: May be that, not all the services that run Internet Connection Sharing (ICS) are enabled. I’d suggest you to make sure the below dependency services are enabled.
Refer the following steps:
a. Click Start, Run, type services.msc, and click OK.
b. To enable a service, find it, double click it,
c. Make sure its startup Type is set to Automatic and service status to be started and click OK.
All the following services must be configured in order to use ICS:
a. Application Layer Gateway Service
b. Network Connections
c. Network Location Awareness (NLA)
d. Plug And Play
e. Remote Access Auto Connection Manager
f. Remote Access Connection Manager
g. Remote Procedure Call (RPC)
h. Telephony
After verifying and/or configuring Automatic startup for each of these services, close the Services window and restart the computer before attempting again to enable ICS.
You may refer:
Using ICS (Internet Connection Sharing)
http://windows.microsoft.com/en-us/windows7/Using-ICS-Internet-Connection-Sharing

Method 2: Based on my online research, the issue seems to occur on computers that have Windows Firewall disabled. Windows Firewall service has to be running even if you’re using another antivirus and firewall program on your computer. I’d recommend you to check for the status of the “Windows Firewall” service and set it to “Automatic”.
Follow these steps:
a. Click “Start”.
b. Type “services.msc” in the Start search box and hit “Enter”.
c. Right-click “Windows Firewall” and click “Properties”.
d. In the “General” tab, select “Automatic” under the “Startup type”.
e. Click “Start” to start the service.
f. Click “Apply” and “OK”. Restart the computer and check if the issue gets fixed.