I want to run forthos(http://www.forthos.org) thru grub for dos(http://newdos.yginfo.net/grubdos.htm). But when grub runs, it says:

Sorry! Currently supported DOS versions are: MS-DOS 3.30 and later; FreeDOS kernel build 2032 and later. […]
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Sorry! Currently supported DOS versions are: MS-DOS 3.30 and later; FreeDOS
kernel build 2032 and later.

Programs such as TSRs and device drivers may also change the BIOS interrupt
vector table. Make sure those programs are not running, then try again

Which version of the dos in DOSBOX is?
How to let dosbox run GRUB? Can dosbox run the forthos directly?
Thanx