When you get a runtime exception error message stating that classes or resources were not found we recommend that you check the class loader of the Web Dynpro application.
Open the Telnet Box, and enter the activating command add deploy, next command llr <application name> (abbreviation stands for “list loader”) to display the class loader. The class loader contains the definition of all the paths and references to which the Web Dynpro application has access. Check if the resource you need is contained in one of the paths. If this is not the case, check if the Web Dynpro application needs a further reference to a library, service or interface.