Another option which I use is to extract the iso with a zip program or winrar and then install from there without mounting it!
Unless of course the iso file itself is corrupt!
Let me know if i can be of further assistance!
I'll not recommended daemon tools coz it install duplex secure sptd driver in machine. It also checks if the driver sptd.sys from Duplex Secure Ltd is present in the system. This driver is used by daemon tools and alcohol 120%. This driver can slow down I/O and basically limit the top speed of your drive when reading/verifying (for some drives on some machines)