Debugging an VSTO and InfoPath 2003 Solution from .Net 1.1
To get the InfoPath to default back to .NET 1.1, you need to update or create a file named INFOPATH.EXE.CONFIG, add it to the same directory as your infopath.exe and add the following:
<?xml version ="1.0" >
Apparently this goes for any old .NET applications.
Please copy the created file “infopath.exe.config” to your Office11 Folder
(eg: C:\Program Files\Microsoft Office\OFFICE11)
This will force InfoPath.exe to be run in the context of .Net 1.1 and not .Net 2.0