I recently had a customer who was having issues when importing drivers to an offline Windows 7 image, but only some of the drivers.
The error they got was:
Error - An error occurred. The driver package could not be installed. For more information, check for log files in the \inf folder of the target image.
Access is denied.
The DISM log file can be found at C:\Windows\Logs\DISM\dism.log
After some troubleshooting we discovered that the driver file they was trying to inject was blocked. After unblocking the file the import worked as expected.
Image of the blocked driver