Update vbac.wsf

When binback option using, if bin directory is not exist then error occurs in "fso.CopyFile".
Coping file from "conf.bin" directory, so do only when "conf.bin" directory exists.
Update vbac.wsf

When dbcompact option useing, if cannot make DAO.DBEngine object then object reference error occurs.
"engine" is defined at line 861, but return undefined when cannot make.
So if "engine" is undefined then don't compact.
revert

revert
Update vbac.wsf
Merge branch 'toatbs-patch-1'
vbac: fix dbcompact bug