Initial screen doesn't load : Loading messarge

[FATXU]

I installed succefully Feng Office 1.7 from zero , but after login as Admin the Intial screen just appears the Logo and the "Loading" message, stuck there (more than 1 hour)
I doesn't appear the Tree directory.

I have another feng office installed (1.6) and I get  this "Loading" message everytime I login but it needs just 2 seconds to load the initial screen, so I undertand it might be some setup configuration.
Any idea what I have to check ?

Thanks in advance

[cabeza]

Clearing your browser cache might help.

[FATXU]

I tried already but it doesn't run.
I also tried in other PC with the same result.
Now I realised that there is an error message at the right bottom of the page:

Detalles de error de página web

Agente de usuario: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; InfoPath.1; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)
Fecha: Sun, 29 Aug 2010 15:47:27 UTC
Mensaje: 'Ext' no está definido
Línea: 9
Carácter: 1
Código: 0
URI: http://www.mypage.com/_office/public/assets/javascript/extjs/ext-all.js
Mensaje: 'Ext' no está definido
Línea: 1
Carácter: 1
Código: 0
URI: http://www.mypage.com/_office/public/assets/javascript/og/extfix.js
Mensaje: 'Ext' no está definido
Línea: 950
Carácter: 1
Código: 0
URI: http://www.mypage.com/_office/public/assets/javascript/og/og.js

The message has more lines but I posted the fist ones.


Thanks

[cabeza]

Are server permissions OK?