I have a puzzling problem when using the IF function.  My spreadsheet
looks like this:

Date          Value          1             2            3             4
1/2006       100
4/2006        450
3/2006        235

If the month in the date in column A matches the month number in the top
row I want to put the value from column B under the matching month
column otherwise I want to insert a zero. So, in the above example, 100
would go in cell C2, 450 in cell F3 etc.  Some date cells will be blank
and I have found that if I use a simple formula like:

=IF(MONTH($A2)=C$1,$B2,"0")

in the cells, the rows with blank dates will always have the value inserted
in column C, i.e it seems like the MONTH function returns a 1 if the date
is blank. So, I figured that I needed a formula like

=IF(ISBLANK($A2)  = FALSE AND MONTH($A2)=C$1,$B2,"0")

but this gives an error.  I have tried a few variations of this with
brackets etc
but I always get an error.

I can't see what is wrong with it!

Thanks for any help.

Seamus