Follow the directions here to remount the Encryption Key
http://support.microsoft.com/kb/887414/en-us
While it shouldn't be necessary you may be required to Take ownership of the Files & Folders so the directions for that is located here
http://support.microsoft.com/default.aspx?scid=kb;en-us;308421
If you didn't backup the Recovery Agent as per M$ Directions when you Encrypted the Data it's gone as that is exactly what you wanted to happen. No Unauthorized Person to be able to access it and anyone without the Encryption Key is an Unauthorized person. :)
Col