Message “Unable to Open Image File DISKIMGx.DAT” (Where x is 3 or 5)

If the message specifies DISKIMG5.DAT, then you need to download the 5.25" image file from https://www.terabyteunlimited.com.

If the message specifies DISKIMG3.DAT, then you need to verify that you have extracted all the files in the BootItNG.zip archive to the same directory. If they are all there and you still get the message, then the current directory is not the proper directory at the time it is run. Either create a shortcut and specify the default directory or change to that directory in a Command Prompt and then type bootitng and press Enter.