Recently I encountered an issue with Microsoft Office SharePoint Server 2007 after installing service pack 1 for the 3.5 .NET Framework. I have reproduced this error under SharePoint 2007 SP1 and now SharePoint 2007 SP2.
The error is not something that a normal user would run into during day to day use of SharePoint. This is one of those things that a developer will most likely encounter.
I used SharePoint Designer to create a data view based upon a call to the queryex method of the SharePoint search.asmx web service. I am not doing anything special here, just running a query and displaying the search results. This works 100% under .NET 3.5 but once .NET 3.5 SP1 is installed the data view will no longer function.
If I open up the page where the web part resides using SharePoint Designer I see the error on the page. Clicking on the show data option in the data source library tab will just display a message that a server error occurred.
Trying to troubleshoot this more I opened up Fiddler to watch the HTTP requests from SharePoint Designer out to the web services. I notice that a request is sent to the webpartpages.asmx web service whenever I click on the show data option in SharePoint Designer. This web service always returns a 500 sever error with no additional details. I looked in the SharePoint logs and in the server event logs and could not gain any more insight into the root cause.
So far the only solution I have is to not apply the .NET 3.5 SP1 update to the servers.
I would love to see a solution so that we can use the SharePoint web services with a data view web part after .NET 3.5 SP1 has been installed.