Dotnetnuke postback failure
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I had a problem in my previous version of a DNN site (6.1.2): Both the "**Copy Page**" and "**Export Page**" functionality don't do anything. I access the forms/pages of either functionalities but when I try to save the page, the loading wheel shows up and goes away but nothing else happens. Now I found out that when I try to create a new portal, I get the same problem: the "**Create new portal**" page appears, validates the fields but when I submit, nothing happens. 

I've upgraded the Website to DNN 6.2.1 and all stays the same. 

**Also, no error is logged in Event Viewer**. This website has a foreign language pack and iFinity URLMaster installed (but these probably have nothing to do with the problem). 

It seems that there is no postback to the server... 

Don't know what else to do... Please help - any ideas are welcome!

Thanks!