[R] Problem mit summaryBy: Group sums gives me "incorrectly" zero for one variable

[Werner Wernersen]

Hi,

first I want to thank all of you for the quick aid
which is provided here on the list during all times.
Thanks a lot for that!

Then, I have a problem using summaryBy which most
probably is a problem of wrong use by me or the like: 

I use this command:
summaryBy(total+total.inf~gr, aE, FUN=sum)

where aE is a 
> str(aE)
'data.frame':   127880 obs. of  16 variables:
 $ gr            : num  2.02e+10 1.13e+10 2.15e+10
4.02e+10 1.04e+10 ...
 $ total         : num  187714   5214   5214 260714  
1304 ...
 $ total.inflated: num  188806   5245   5245 262230  
1311 ...
..
..
..

Now, the resulting sum for total.inf per gr is
perfectly fine but for the sum for total per gr I get
only zeroes although they shouldn't be zero. 

Has anybody experienced a similar problem? What am I
doing wrong?

Thank you very much for your help,
  Werner