Java isn't required, however make sure that your Java engine is the latest and uninstall any older ones as they are a security risk.
McAfee relies on Internet Explorer, whether or not you use it, so go to IE Tools/Internet Options
If IE6 set all the zones under the Security tab to default click Apply, go to the Advanced tab and set to default, click Apply, go the Content tab and make sure that Content Advisor is OFF.
If IE7 or 8 go to Advanced tab and click Reset then Apply and OK. Close and reopen IE7/8 and go to Tools/Manage Add-Ons and re-enable all the add-ons.
Try a manual update to see if the arrow icon appears.
My DAT is 5623 which came in when I started up this morning. Double-click the taskbar icon to open Security Center and then click About at the lower right-hand corner and see what yours is.