The way I solved this problem was simple. I had the option of installing Ubuntu 18.04 LTS, either using uefi mode or the device boot option (invoked through the BIOS startup by pressing ESC or F2). When I installed using uefi mode, I got this error. What I did next was to boot my USB through the device boot option in the BIOS startup and there was no aforementioned problem.
The way I solved this problem was simple. I had the option of installing Ubuntu 18.04 LTS, either using uefi mode or the device boot option (invoked through the BIOS startup by pressing ESC or F2). When I installed using uefi mode, I got this error. What I did next was to boot my USB through the device boot option in the BIOS startup and there was no aforementioned problem.
That is how I escaped the error. Hope this helps.