During the server installation, you use the Load Driver feature to attempt to load a storage driver but it fails to find an appropriate driver.
The load driver feature will search for a file named oemsetup.inf. The file must be named exactly oemsetup.inf in lower case. If the file exists but has uppercase letters, the load driver feature will fail to find it.
If the oemsetup.inf file contains uppercase letters, rename the file to all lower case letters and try to load the driver again.
If you are using the driver, MegaSR.INF, copy this file and rename it to oemsetup.inf in all lower case letters. Then try to load the driver again.