Possible reasons for not being able to modify a Web Part connection include

• You are only browsing the Web Part Page. You can delete or modify connections between Web Parts only when you are designing the page.
• You may not have permission to delete or modify Web Part connections. The Web Part developer or site administrator does not want connections to be modified or deleted on this Web Part Page.
• You are not using the correct browser. You must use Internet Explorer version 5.5 or later to delete a connection between Web Parts.
• The connection between two Web Parts is broken. You or another user deleted or disabled a Web Part after you made a connection to it.
• The Web Part connection was created in another program. You cannot delete or modify this connection through the browser. To delete or modify this connection, you must use an HTML editor compatible with Windows SharePoint Services, such as Microsoft Office FrontPage 2003.
• The Web Part you are trying to connect to is a static Web Part. To modify this connection, you must use a Windows SharePoint Services—compatible HTML editor, such as Microsoft Office FrontPage 2003.
• A column in the Create/Edit Connection dialog box is not available. You attempted to modify a connection and the previous column selected no longer exists in the Column list because the list of columns was changed by another user. Select another column.