=(G3/$L$1)+$D$1
The only way that you'd get a #VALUE! error with that formula is if any of
the referenced cells contained a TEXT entry or if any of those cells already
contained a #VALUE! error.
Try this for a return of 0:
=IF(ISERROR((G3/$L$1)+$D$1),0,(G3/$L$1)+$D$1)
Or this to return a blank:
=IF(ISERROR((G3/$L$1)+$D$1),"",(G3/$L$1)+$D$1)
Both formulas will trap *all* errors.