Every once in a blue moon (ie. after i have just sent it to a client), after installing my program (and everything that goes with it - CF SP1, SQLCE etc), I get a TypeLoadException, thrown by System.Data.DataSet. I dont think I am doing anything fancy with a dataset (just reading from databases, files (using .ReadXML) and XmlTextReaders). The version stated in the error is 1.0.5000 - the same as the version I have here that works. Has anybody else ever come across this? anybody have any idea what could cause this?