Problem with Statistics

[MaxPower19]

Hi to everybody!!
I have a problem using WSO2 ESB v1.7... In fact sometimes the page of "statistics" is never updated, even if the "system logs" and "trace message" sections are correct.
I use:
*Windows Vista SP1;
*Microsoft Internet Explorer 7 (with Firefox an ESB I have a lot of trouble);
*JDK 1.6.
Someone have a solution?
Thanks!!