Doing Forms With Just Windows SharePoint Services 3.0

WSS has a basic UI for setting item-level permission on list items, but they hide that from the UI for document libraries. If you go into Settings->List Settings->Avanced settings for a list, you'll see the options to do pretty much what you're asking for. However, on document libraries, that UI is not available. The settings it drives, though are avaiable via the object model.

You could set those same properties for a document library like this:

SPDocumentLibrary onlyOwnLib = theWeb.Lists["DocLibName"]  
onlyOwnLib.WriteSecurity = 2;  
onlyOwnLib.Update();  

And that should about do it. However, apparently that doesn't really set permissions; it just controls what the user can do via the UI. If they had another interface to the library (like via WebDAV) or list (like via the web services), it wouldn't prevent them from editing items they didn't create. If you want true item-level permissions, I think you need to go the event handler route.

This post from Matt Morse explains it in more detail, and he even wrote a command line tool to set the property (plus the .ReadSecurity property) for lists and libraries.

Here are a few ideas on what you could try:

• Fiddler should be able to tell you if there is a network problem.

• Check the HTML for anything unusual. Is it malformed in any way? Can you save a copy and run it through an online validator (although this is limited in use as SharePoint's default markup isn't compliant).

• If some users are having the issues but others aren't, check their permissions on the server.

• You could also try using the SharePoint "Log in as another user" feature to see if the problem can be reproduced on your machine when logged in as them. You may also want to try running Internet Explorer as that user.

• Check the Event Viewer on both client and server for anything unusual.

• Check the IIS logs on the server for any errors.

• Check the SharePoint ULS logs on the server in the "12 Hive" for errors that might be related to this problem.

• Try running Process Monitor on the client and reproduce the problem. Search for keywords such as FAIL or ERROR to see if anything appears. Make a note of the time the problem occurs and see if the Process Monitor logs give any additional information.