How did you do the upgrade? Did you follow the instructions in the Release Notes?
What web broswer are you using?
What version of vCenter Server?
Have you tried IE8 or IE9 to see if you get the same result?
I got the same thing, blank dashboard in firefox and IE so I ended up rolling back to 5.0.3.
It seems that it works in IE8. So why would it not work in Chrome if 5.0.3 worked fine in Chrome?
**Well it seems that I had to delete my cache and all past history and cookies from my browser to allow Chrome to see the dashboard. Very strange how I could see all other tabs but the dashboard.
cleaning browser cache on Chrome or FF should fix this.