Environment
Two ESXi Servers = Esxi1 and Esxi2
version of Esxi Servers = 5.0
Vcenter OS = Windows2008R2(64bit)
SAN = iscsi SAN attached on both Esxi Servers
HA and DRS = enabled
Application HA = 5.1 SP2
Application HA OS = rhel 5.6 (64bit)
Problem
Application HA tab shows ""This program cannot display the webpage"" / ""Navigation to the web page was canceled"". See the below snap for reference:
Solution:
The machine where Vsphere Client is installed and Application HA console too. On that machine Browser Proxy must be disabled or either by pass the Vcenter machine IP Address under internet browser, In my case I had proxy defined under Microsoft Internet Explorer. So that you will be able to see the proper page of Application HA. Also logout the Vsphere Client and re-loggin it again.