This solution solved my problem too. Thanks xDthat msg sometimes occur when .net framework is not updated. Though you can run the pingzapper.
In Pingzapper
Simply just create a custom game
name: (anything)
Main game filelay.exe
Launcher File: mu.exe
\\next
Server:Europe
\\finish
And On
Go to your IMU folder and locate mu.exe
and run it.. DONT click the custom game u createdin pingzapper..
thanks