The file it fails to find may be USBSER.SYS.
You may need to copy this from archive.
Windows 7 (x64 64bit)
- Source of usbser.sys: C:\Windows\System 32\DriverStore\FileRepository\mdmcpq.inf_amd64_neutral_9bb71004e7b8f7ae (archive file)
- Destination to copy: C:\Windows\System 32\drivers
On our systems the hex digits at the end are slightly different to the above.
The source of this information is here:http://www.microchip.com/forums/tm.aspx?m=488342