Newbie here. Not very experienced with CLI. I've run into this problem twice, now, and I can't help but suspect some other folks have struggled with it and finally just given up. There are one or two things I do only in Windows and I'd rather do it in a VM in Linux (where it actually seems to behave better than it does on its own literal install???).
Anyway, I thought maybe it would make someone's day a little less unbearable (assuming you're having one of those--if not, maybe it'll make your good day better) if they had a lickety-split guide on how to do this smoothly through the GUI.
There appears to be different problems and solutions with regard to this error. I don't know the exact origin of the problem, but I pretty much tried everything I could find on it and in the end it worked so, hopefully, others will have, at worst, the same outcome.
On the face of it, it seems like a conflict between the existing host system kernel and driver or module needed to get VirtualBox emulating the guest system.
The first thing I did was to find out exactly which version of the Linux kernel my Manjaro (Xfce, btw) system was running on, which is as easy as: System Main Menu - Settings - Manjaro Settings Manager - Kernel
You will then see a list of available kernels. Some will be installed, some won't be, but only one should be running. You will need the version number of the running (active) kernel available for reference later on, so make a note of this if you're not a number rememberer person.
Next, install the needed files by going back to the Main Menu, then System - Add/Remove Software (PAMAC), then typ "virt" into the search field. You'll see quite a few options, many may already be installed, but you should only need to check 4 boxes--the ones beside "virtualbox-guest-dkms," "virtualbox-host-dkms," and the virtualbox host and guest modules that most closely match your active kernel version number. NOTE: Do not choose modules that specify RT (real-time) operating kernels. You will be asked to choose kernel version numbers again, and optional dependencies. Check only the ones that specify the Manjaro distribution. Then proceed as usual with the installation. You may or may not need to restart your system for the changes to take affect.
Some of this may be overkill, but again, it worked for me in the end, and I'm of a mind to stick with the old "If it ain't broke, don't fix it" axiom.
Happy Trails To You