ST6 Maintenance Packs can be downloaded from:
If you're using Norton Internet Security, you'll get an a screen like this:
Just click "Run this program anyway"
You also may get this when starting Solid Edge next time....
Again just click on "This program installed correctly"
Everything works fine... you should not have any problems.
If you are under active Solid Edge maintenance then you are able to download any Solid Edge service/maintenance pack for yourself. You will need your WebKey account details to access the Solid Edge downloads section:
Or you can ask your Solid Edge support contact to help provide you the service pack.