Came across this error today and thought I would pass it on related to Sage Payment Exchange desktop 2.0 and ""Unhandled exception has occurred in your application"" when opening Sage Exchange Desktop 2.x
Products
FIX
Uninstall Sage Exchange Desktop (Start, Control Panel, Programs and Features)
Open C:\ProgramData
Right-click 'Sage Payment Solutions'
Rename to 'Sage Payments Solutions_old'
Open C:\Users\UserName\AppData\Local\Sage Payment Solutions (where UserName = Windows username)
Rename the Sage Exchange folder located here to Sage Exchange.Old
Browse to the MAS90\Wksetup folder and run Autorun.exe
Select the option to install Sage Exchange Desktop
Proceed with the installation and test SE once it finishes
Module SDK should be repaired during this process, but for older versions, it is possible you might have to manually repair it.