adding dashlet throws permission error

[donduma]

Hello,

if i want to add a new dashlet including a diagram, an error occurs. First its loading... then an alert box says "failed".

In Firebug i see the line:
You don't have permission to access /sugarsuite/cache/xml/c2e32ada-a818-0df7-a5fc-4d78ada5c854_a14aa61f-610a-3ea9-89d3-4e958f65fa8e.js

The Settings on the "cache"- Folder are 775.
If i look into the /cache/xml Folder, the file c2e32ada-a818-0df7-a5fc-4d78ada5c854_a14aa61f-610a-3ea9-89d3-4e958f65fa8e.js exists and its permission setting is set to 660. Why is it set to 660? Is this a bug? Can anybody help?

If i manually change permissions of the .js file over ftp to 666 and reload the page , the diagrams are shown well.

my sugar:
Sugar Community Edition 6.2.1 (Build 6405) on linux