Increase Java heap space

Hi friends :

I built 100.000 users on Sql server for test Openfire and I added then to e group.

Now, when I click on group, I see this error : java.lang.OutOfMemoryError: Java heap space...

I did belows for solution of error, but It did'nt change the Openfire.

(I installed Openfire on Win7)

...If you use OpenFire as a service configured in Windows, create a file with the openfire-service.vmoptions name and place within it the following parameters one below the other as they are.
-Xms512m
-Xmx1024m

...

Thanks.