When you try to access to a Datasheet View and if you have Office 2010 64-bit installed, you’ll get the following warning:

The list cannot be displayed in Datasheet view for one or more of the following reasons:

– A datasheet component compatible with Microsoft SharePoint Foundation is not installed.
– Your web browser does not support ActiveX controls
– A component is not properly configured for 32- or 64-bit support.

Solution:
Try to install 2007 Office System Driver: Data Connectivity Components after you have installed Office 2010 64-bit on the client machine. This should provide you with the edit in Datasheet functionality.