Cannot locate form: <form name>
What happened
You tried to open a document created with a form that doesn't exist in the active application; someone might have pasted the document into the application instead of creating it from the Create menu.
What you can do
To view the document, click OK. This opens the document using the application's default form. However, some data in the document may not appear if the default form doesn't have all the fields contained in the original form.
Tip: If you paste documents from one application
into another frequently, and you have Designer access to the target
application, paste a copy of the appropriate form there.
For more information on working with forms, see HCL Domino® Designer Help if you have it installed. Or, go to Documentation on the Web to download or view Domino® Designer Help.