Error message when you try to attach a file in a custom form on the Web site in Windows SharePoint Services 3.0: “This form was customized not working with attachment”
I’ve had several clients ask about this, and my answer to date has been “It’s a known ‘feature’ or bug.” I just ran across this Microsoft KB article that shows you how to fix this issue by loading the 953749 hotfix: SYMPTOMS You use Microsoft Office SharePoint Designer 2007 to add a Custom List Form…