I'm having problems with the SUMIF function

If I use
=SUMIF('Page 1'!$E$4:$E$260,"=A2",'Page 1'!$H$4:$H$260) I get a zero result

If I use
=SUMIF('Page 1'!$E$4:$E$260,A2,'Page 1'!$H$4:$H$260) I get an accurate
result

For my final function I want to use
=SUMIF('Page 1'!$E$4:$E$260,=A2,'Page 1'!$H$4:$H$260)-SUMIF('Page
1'!$F$4:$F$260,=A3,'Page 1'!$H$4:$H$260)
....to get the sum of days within a date range. A, E and F are all date
formatted Columns. H is a number format (days).

I also have 100 rows, so it would be good if I am able to drag =A2, so that
it updates to =A3,= A4,= A5, etc., on the cells below.

Please help!

Dylan
Scotland