Error : when logging in the back office

[saladin]

Could someone help me with the following error ? This happens when I log in the Back office,

see the result of the explorer , here under

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ERROR
The requested URL could not be retrieved

While trying to retrieve the URL:

The following error was encountered:

Zero Sized Reply

Squid did not receive any data for this request.

Your cache administrator is webmaster.
Generated Sat, 11 Sep 2010 16:06:52 GMT by demil1.byetcluster.com (Lusca/LUSCA_HEAD-r14705)