Subject SUM, group by
Author Planles

I have following select statement, which reports me an error (error
code -104, invalid expression in the select list):

select Field1,Field2, Field3,
SUM(Field4) as SField4,
SUM(Field5) as SField5,
SUM(Field6) as SField6
from TABLE
group by Field1
order by Field1

I want to get a sum of fields 4,5,6 for each of Field1.

What am I missing here ?