I have only one web part but e.g. configuration and default text has been saved properly. Also when I try Corporate Site the same web part is saving data correctly. (I stopped current website, ran Corporate Site and test)
Also I removed this one and added other one without any modification (just insert web part) and still the same error :(
Eventlog:
Event ID: 585
Event type: Information
Event time: 12/3/2012 2:25:02 PM
Source: Content
Event code: UPDATEDOC
User ID: 53
User name: administrator
IP address: 127.0.0.1
Node ID: 549
Document name: /
Description: Update document /
Site name: HrSolutionsPortal
Machine name: R8NGBA3
Event URL: /KenticoCMS_6.0SP1/cms/getdoc/ad7c1df2-b740-4288-bf92-39e24df5c2a0/default.aspx
URL referrer: http://localhost:2132/KenticoCMS_6.0SP1/cms/getdoc/ad7c1df2-b740-4288-bf92-39e24df5c2a0/default.aspx
User agent: Mozilla/5.0 (Windows NT 5.1; rv:16.0) Gecko/20100101 Firefox/16.0