- Open the manifest.xsf in notepad.
- PublishUrl: Search for "publishurl". I believe, this pointed to the old location other than what actual the form is submitted to. Make it empty [No problem].
- runtimeCompatibilityURL: in the notepad, search again for "runtimeCompatibilityURL". Now change its value to "http://sharepointserver/_vti_bin/FormsServices.asmx".
- If you are using the source control like VSS, Source vault, TFS or whatever then you have to do below things.
- Open Visual Studio and checkout all the files in the Infopath Form Template folder.
- Once all checked out, then close the Visual Studio and reopen.
Check for more information here. MSDN
That's it. Now, you have to reopen the file and do whatever changes you have to do. Enjoy.