it looks like your missing a select statement. something like below. might need more tweeking but hopefully it works.
With Wdapp.Selection .ClearFormatting .Find.Execute FindText:="seed", Format:=False, Forward:=True '***line below errors '.Expand Unit:=wdParagraph '<> If .Find.Found Then .Select Selection.Expand Unit:=wdParagraph End If '</> End With