Can't run 'masm386'

[Andre Tampubolon]

I was trying to build druntime. I got this error:
dmd -c -d -o- -Isrc -Iimport -Hfimport\core\sys\windows\windows.di
src\core\sys\windows\windows.d

dmc -c  src\core\stdc\errno.c -oerrno_c.obj

dmc -c  src\rt\complex.c

dmc -c  src\rt\minit.asm
masm386 -DM_I386=1 -D_WIN32 -Mx src\rt\minit.asm;

Can't run 'masm386', check PATH
masm386 -DM_I386=1 -D_WIN32 -Mx src\rt\minit.asm;

Can't run 'masm386', check PATH
Error: 'dmc' not found

Strange. This thing never happened before.