TypeLoadException??

I'm implemeting an application for a smartdevice using c# and all through the implementation things were goin fine, and suddenly the same function that was called peacefully started generating a TypeLoadExcpetion. I don't understand why. This is t the function call: try { exporter.Export(this.currentProject, fileName); } catch (TypeLoadException ee) { MessageBox.Show("second" + ee.Message); } and this is the function until the exception takes place: public void Export(Projects project, string filename) { s.WriteLine("here2"); s.WriteLine(project.getpID().ToString()); s.WriteLine(filename); XmlDocument myDoc = new XmlDocument(); If anyone knows the solution, please inform me.. Thanks Sageda