I have a SharePoint list of URLs which I have converted to an XSLT
data view web part in FrontPage. At first my list data appears
correctly. After some period of time (usually overnight), I get the
following error message when viewing the page in my browser:

"Unable to display this Web Part. To troubleshoot the problem, open
this Web page in a Windows SharePoint Services-compatible HTML editor
such as FrontPage. If the problem persists, contact your Web server
administrator"

But, when I open the page in FrontPage I can see the data in both
design and preview mode and have no trouble connecting to the
datasource.

Has anyone run across this when using data views?