Response from Logitech Support (didn't fix my issue, what did is at the very bottom) YMMV 
:
Make sure that you have the administrator's permission on your computer. You may try to uninstall the current headset software that you have and disable your firewall / anti-virus
temporarily. Then perform a clean boot installation as follows:
Clean Boot:
1. Click Start type msconfig in the search box and press Enter
Configure Selective Startup options
1. On the General tab, choose Selective Startup
2. Uncheck Load Startup Items
3. Select the Services tab
4. Check Hide all Microsoft services
5. Click Disable all
6. Click on OK
7. Click Restart.
Then reinstall and run the software using this download link: http://www.logitech.com/en-us/438/7248?softwareid=
Wait for a moment and see if the software will automatically launch after a while.
After performing the necessary steps, restore your system by doing the following:
1. Click Start --> Run --> Type MSCONFIG--> Click OK
2. On the General tab, choose Normal Startup
3. Click OK
4. Click YES, when asked to restart your computer
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However, that alone didn't fix my troubles. What seemed to fix it was I browsed to the ereg.exe and ran as admin. I registered the product, and afterwards rebooted the PC. So far no more runtime error.
