TException is the base class for all PRADO exceptions.
TException provides the functionality of translating an error code
into a descriptive error message in a language that is preferred
by user browser. Additional parameters may be passed together with
the error code so that the translated message contains more detailed
information.
By default, TException looks for a message file by calling
{@link getErrorMessageFile()} method, which uses the "message-xx.txt"
file located under "System.Exceptions" folder, where "xx" is the
code of the user preferred language. If such a file is not found,
"message.txt" will be used instead.