Im currently buiolding a site for a client, but suddenly i cant insert images with the media picker...

I get the following javascript error:

Brugeragent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; MDDS)
Tidsstempling: Thu, 16 Dec 2010 10:05:00 UTC

Meddelelse: '_itemPickerUrl' er null eller ikke et objekt
Linje: 78
Tegn: 648
Kode: 0

URI: http://dev.xxxxxxxxxxxxxxxxxxxxxxx.dk/umbraco/DependencyHandler.axd?s=L1dlYlJlc291cmNlLmF4ZD9kPUN4MUE4R21KbnNpbzVTZFp5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&t=Javascript&cdv=1


Meddelelse: 'UmbracoImageViewerAPI()' er null eller ikke et objekt
Linje: 138
Tegn: 17
Kode: 0

Any idea why this suddenly happens? I have only worked in the UI. Not on any phsycal files in the install...