I have a project which also uses the 16c74a.  Sometimes I have the same
problem with lines 1 and 3; however, it is caused because I forget to turn
off my debug switch.  This switch comments out a power up delay for the LCD.
( I do this for simulation) So my first comment is confirm that your power
up delay is long enough.  I also experienced the problem when I replaced one
brand of LCD with another.  I had to insert a small delay in my busy flag
routine. (I monitor the busy flag pin14 for completion of the command)  I do
not know for sure why I had to do this, but it works now.
Good Luck
Kevin