WProgram.h was a 'header' file that was used with the older Arduino libraries. With the switch to version 1.0 of the IDE they have basically renamed this header to Arduino.h - the problem being that it essentially broke every 3rd-party library out there.
There are some additional changes that were made which further broke a bunch of libraries, such as some changes to the Wire library. Wire is used for I2C and this is used by the real time clock. They changed the names of two functions, so every library that used Wire needed to be changed to work with the new terminology.
You should be able to just download the latest version of the RTC library from github:https://github.com/adafruit/RTClib
That should compile fine under Arduino 1.0. Simply delete the RTC library in your libraries folder, then unzip the new one and follow the directions in its readme file.
Actually I think the DHT library has similarily been updated. You don't need to re-download it now that you've got it working, but it never hurts to have the latest version just incase there were other changes:https://github.com/adafruit/DHT-sensor-library