Launching vSphere Client generates the error "The type initializer for 'Virualilinfrastructure.Utils.CLientsXml' threw an exception"

Hello all,

I am running vSphere 5.5 on a 2012 Microsoft Server and getting this error. Can anyone let me know what is causing it and what is the fix. Also if i do upgrade this client will it cause an issue detecting the virtual clients previously set up

thank you