I'm having the same problem, and into the DEMO page of this site, too!
But I've seen that other counters have not this problem... 

How can be solved or why ocurr it?

Hi Teller, I have fixed it!!   

Replace the following lines of counter.php file:

392, 395 and 405

And change:
return number_format ( $counter , 0 , "," , "." );
to
return $counter;
on each one.

On line 457 already there is a "number_format" call, so previous calls on changed lines where unnecesary.

Make a backup copy of counter.php to be sure.

Regards, Damian.