I found out that the pie chart not showing corectly is a browser issue.
In firefox it works 100% correctly.
In Internet explore, it shows only the graph but it doesnt show the "legend" at all.

I tried the joomla ie8 compatibility plugin but this didnt solve the problem.

Also, in IE on the bottom left corner ,i get this yellow symbol (dont know the english word for it)
and when i ckick it, i see the below error which i dont know if it is related to the first issue i mentioned above:

??????: ?? ?????? ??? ????? ??????.
??????: 7
??????????: 33504
???????: 0
URI: http://www.multipolls.gr/components/com ... ael-min.js