I have a holiday spreadsheet that I've used for the last three years
which was passed down to me when I took over this role.

At the top of the spreadsheet, it works out sick days, holiday
allowance, etc. It also works out full days (with the letter H) and
half days (with the letter G). This was the formula that was used:

{=(SUM(IF(C17:D382="g",0.5)))}

The 2010 spreadsheet no longer accepts this formula and gives me a
#VALUE! error instead. It also does not allow me to enter the {}
brackets. The range is correct and nothing has changed except the
dates.

Any ideas?