In your SharePoint application you have a list, and you want to show this list in a datasheet. After selecting this option from the Actions-menu, you will get an error:
On your machine you have Office 2007 installed, so, the first hint doesn’t seem to be the reason. In your Internet Explorer you have activated all ActiveX-options, so, everything seems to be right, but you still get this error message.
To solve this problem open RegEdit and find HKEY_LOCAL_MASCHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility. Here you shoud find an entry with CLSID 65BCBEE4-7728-41A0-97BE-14E1CAE36AAE. Remove this entry, close RegEdit and restart your Internet Explorer. Now, the error message should disappear and the datasheet is shown.